医疗保健 知识点题库

根据短文内容，选择最佳答案。

When thinking about quitting(停止) smoking…

    List all the reasons why you want to quit. Every night before going to bed, repeat one of the reasons 10 times.

Decide positively that you want to quit. Try to avoid negative thoughts about how difficult it might be. Develop strong personal reasons as well as your health and responsibility to others. For example, think of all the time you waste taking cigarette breaks, rushing out to buy a pack, hunting a light, etc. Set a date for quitting — perhaps a special day like your birthday, a holiday. If you smoke heavily at work, quit during your vacation. Make the date holy seriously, and don't let anything change it. Begin to condition yourself physically; start a modest (适当的) exercise; drink more water; get plenty of rest.

    Immediately after quitting...

    The first few days after you quit, spend as much free time as possible in places where smoking is prohibited, e.g. libraries, museums, theatres, department stores, etc.

    Drink large quantities of water and fruit juice. Try to avoid wine, coffee, and other drinks which remind you of cigarette smoking.

    Strike up a conversation with someone instead of a match for a cigarette.

    If you miss the feeling of having a cigarette in your hand, play with something else - a pencil, a pen, a ruler. If you miss having something in your mouth, try a fake (仿制的) cigarette.

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    Conventional wisdom says that hardship can make us old before our time. In fact, a new study suggests that violence not only leaves long-term scars on children's bodies, but also changes their DNA, causing changes that are equal to seven to ten years of premature aging.

    Scientists measured this by studying the ends of children's chromosomes (染色体), called telomeres (端粒), says Idan Shalev, lead author of a study published in Molecular Psychiatry.

    Telomeres are special DNA sequences (序列) which prevent the DNA in chromosomes from separating. They get shorter each time a cell divides, until a cell cannot divide any more and dies.

    Several factors have been found to shorten telomeres, including smoking, radiation and psychological stresses such as being treated badly when young and taking care of a chronically ill person.

    In this study, researchers examined whether exposure to violence could make children's telomeres shorten faster than normal. They interviewed the mothers of 236 children at ages 5, 7 and 10, asking whether the youngsters had been exposed to domestic violence between the mother and her partner; physical maltreatment by an adult; or bullying. Researchers measured the children's telomeres-in cells obtained by wiping the insides of their cheeks-at ages 5 and 10.

    Telomeres shortened faster in kids exposed to two or more types of violence, says Shalev. Unless that pattern changes, the study suggests, these kids could be expected to develop diseases of aging, such as heart attacks or memory loss, seven to 10 years earlier than their peers.

    Shalev says there is hope for these kids. His study found that, in rare cases, telomeres can lengthen. Better nutrition, exercise and stress reduction three things that may be able to lengthen telomeres, he says.

    The study confirms a small but growing number of studies suggesting that early childhood a adversity imprints itself in our chromosomes, says Charles Nelson, a professor of pediatrics and neuroscience at Harvard Medical School.

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    Peter Thiel,the billionaire co-founder of PayPal,plans to live to be 120.Compared with some other tech billionaires,he doesn't seem particularly ambitious.Dmitry Itskov,the “godfather” of the Russian Internet,says his goal is to live to 10.000;and Sergey Brin,co-founder of Google,hopes to someday "cure death.

    They aren't being ridiculous.Their search is based on real science that could fundamentally change what we know about life and about death.It's hard to believe,though,since the human search for immortality is both ancient and filled with disastrous failures.Around 200 B.C.,the first emperor of China,Qin Shi Huang,accidentally killed himself trying to live forever;he poisoned himself by eating mercury（水银）pills.Centuries later, the search for eternal life wasn't much safer: In J492,Pope Innocent VIII died after blood transfusions from three healthy boys whose youth he believed he could absorb.

    But historical examples haven't discouraged some of the biggest names in Silicon Valley.Thiel,for example,has given $3.5 million to the Methuselah Foundation.Aubrey de Grey,Methuselah's co-founder,says SENS,the nonprofit's main research is devoted to finding drugs that cure several types of age-related damage:"Loss of cells, excessive（过多的）cell division,inadequate cell death,garbage inside the cell,garbage outside the cell,...The idea is that the human body,being a machine,has a structure that determines all aspects of its function,so if we can restore that structure—at the molecular（分子的）and cellular（细胞的）level—then we will restore function too,so we will have comprehensively renewed the body."

    But SENS,which has an annual operating budget of $5 million,is small,compared with the Brin-led Project Calico,Google's attempt to “cure death,”which is planning to pump billions into a partnership with medicine giant AbbVie.Google is secretive,but it's said to be building a drug to copy a gene associated with exceptional life span.

    Then there's the Glenn Foundation for Medical Research,started by Paul F.Glenn in 1965.Since 2007,the foundation has distributed annual "Glenn Awards,"$60,000 to independent researchers doing promising work on aging.The Glenn Foundation also works closely with the Ellison Medical Foundation,a far younger institution (founded in 1997).Ellison's passion project gives out hundreds of thousands of dollars each year to scholars seeking research on aging.Their decision to fund independent research may be paying off.Research projects funded by Ellison and Glenn appear to be developing into a testable means to stave off old age—for lab mice.The question is: Can those lab results be repeated in humans?

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    When seeing the doctor, you feel better to know you will get some medicine. But the doctor knows that medicine is not always needed. Sometimes all a sick person needs is some reassurance (安想) that all will be well. In such cases the doctor may prescribe a placebo.

    A placebo is a sugar pill, a harmless shot, or an empty capsule. The patient thinks it is medicine and begins to get better. How does this happen?

    The study of the placebo opens up new knowledge about the way the human body can heal itself. It is as if there was a doctor in each of us. The doctor will heal the body for us if we let it. But it is not yet known just how the placebo works to heal the body. Some people say it works because the human mind fools itself. These people say that if the mind is fooled into thinking it got medicine, then it will act as if it did, and the body will feel better.

    Placebos don't always work. The success of this treatment seems to rest a lot with the relationship between the patient and the doctor. If the patient has lots of trust in the doctor and if the doctor really wants to help the patient, then the placebo is more likely to work. So in a way, the doctor is the most powerful placebo of all.

    A placebo can also have bad effects. If patients expect a bad reaction to medicine, then they'll also show a bad reaction to the placebo. Some doctors still think that if the placebo can have bad effects it should never be used. They think there is still not enough known about it.

    The strange power of the placebo does seem to suggest that the human mind is stronger than we think it is. There are people who say you can heal your body by using your mind. And the interesting thing is that even people who swear this is not possible have been healed by a placebo.

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    In the rush to get to school, you drop a piece of toast on the floor. Do you throw it away or decide it's still OK to eat? If you're like most people, you eat it. Maybe you follow the “5-second rule”, which says foods are safe to eat if you pick them up within 5 seconds after dropping them. But you might want to think again. Scientists now say that 5 seconds is all it takes for foods to become polluted with enough bacteria to make you sick.

    Bacteria can cause many kinds of illnesses. Some kinds of bacteria can grow on food. If you eat foods on which these bacteria are growing, you can become sick.

    One of these food-borne bacteria is Salmonella. It makes 1.4 million people sick every year. Salmonella is often found in raw eggs and chicken. Cooking kills these bacteria, which is why it is so important to cook eggs, chicken, and other foods thoroughly.

    But how long does it take these bacteria to pollute food? A team of scientists in South Carolina did an experiment. First, they placed an amount of Salmonella on three surfaces: wood, tile, and carpet. They placed a piece of bread and a piece of sausage on each surface for 5, 30, or 60 seconds. After just 5 seconds, both the bread and the sausage picked up enough bacteria to make you sick.

    So, forget the 5-second rule. If your toast drops on the floor, throw it away and get another piece of clean toast. And next time, be careful not to drop it!

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    It is a cold and dry winter morning. When you wake up, you feel that your throat hurts. You begin to sneeze and later you may cough. You must have a cold! Wait a moment. Could it just be a common cold or the flu that's been going around?

    A cold gives you a runny nose and cough. But it's usually easy to deal with. Some take medicine while others drink herbal tea or chicken soup. Usually you feel better after a week.

    On the other hand, the flu can be much more dangerous. It usually gives you fever.

    Sometimes it can cause death. According to an American magazine, the worst flu killed about 50 million people from 1918 to 1919.

    Don't worry. If you get a flu vaccine（疫苗）, it can stop you from getting the virus. Flu vaccines work by giving the body a small amount of flu viruses. This causes your body to develop antibodies. So next time you get the flu, the antibodies should help you.

    The flu virus changes every few years. Therefore, there are so many types of flu, such as H1N1 and H5N1. The antibodies for one type of flu can't help us against all types of flu. That's why we need to get vaccine every year.

    However, good health habits may also help stop you developing a cold or flu. Washing your hands often helps stop you from getting viruses. It is also important to get regular exercise and eat healthy food. All these can help you strengthen your immune system.

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    This year's flu season is pretty scary. To try to minimize the effects, public officials are still urging anyone who hasn't yet gotten their flu shot to get one as soon as possible. However, even if every single person got a shot in the arm, the vaccine(疫苗)—with its excellent 36 percent effectiveness—would not prevent everyone from getting infected with the annoying virus. Knowledge is power, so here's what goes on in your body when you come down with the flu.

    The influenza virus primarily attacks your nose, throat, and the tubes that lead to your lungs. But the flu is so much more than that. Your muscles ache, your head hurts, and your appetite goes down, among other things. To our surprise, almost all of these symptoms have less to do with the virus itself than with your immune(免疫的)response to them. Unfortunately, the very defense you have in place to get rid of the flu is the reason you feel so painful when you recover.

    The virus usually enters through your mouth, typically by way of your hands But it takes a few days for symptoms to set in. While this process might cause some harm to your nose and throat, it's nothing major, and nothing like the symptoms that typically accompany a bad or even mild case of the flu.

    The real fun starts when your immune system begins to fight. Your immune system comes in two parts: the innate system and the adaptive. The innate immune system is essentially an all-purpose tool. As soon as your body senses the presence of any injury or invader (入侵者), the innate immune system launches into action by producing tiny proteins called cytokines and chemokines. The cytokines reproduce almost immediately and start to attack the virus. This increase in immune cells creates an serious inflammation(炎症) throughout the body. But the worst is still to come. Meanwhile, the chemokines work with the adaptive immune system to help create T cells. These cells are a special type of white blood cell that works in a much more specific way: They find the influenza virus, identify what's special about it, and create something unique on their surface that finds and destroys similar invaders.

阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。

    There's a word of wellness I've loved for years. It's HALT: the idea that if you want to be calm and content, never let yourself get too hungry, angry, lonely or tired. Researchers are increasingly looking more closely at the "L" in "HALT", with one report presented to the American Psychological Association finding that long-term loneliness might be a greater public health risk than obesity.

    Loneliness is a problem with many faces. Some people are alone most of the time—data collected by the United Kingdom found that 200, 000 people over the age of 75 had not had a conversation with a friend or a relative in more than a month. But some people feel lonely even in a crowded room, disconnected from meaningful relationships even though their days are filled with people.

    To me, walking a positive path means walking alongside others—people who lift our spirits, share our values, challenge us to grow and learn and bring us joy. But social satisfaction doesn't come automatically or even easily to too many people. And in our age of individualized electronic devices, social media and text-based communication, it can be harder than ever to feel truly connected to others.

    I was so heartened to read that recently the British Parliament (议会) has created a "Minister for Loneliness" position to promote research, education and principles so as to cure what some researchers call "the loneliness disease". More and more doctors in America are also screening adult patients for loneliness at annual physical examinations, which is another promising sign.

    With proper social support and community participation, loneliness can be prevented from happening. If you are feeling lonely, make a list of your daily routines and ask yourself how you could add more social interactions to each day. Try reaching out for volunteer opportunities, clubs and organizations to join and old friendships to renew. If you are struggling, ask a consultant to help you identify your social obstacles and overcome them.

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    After moving to the United States, immigrant groups trying to fit in tend to choose high calorie fatty foods in an attempt to appear more American, a new study finds. That's one reason why immigrants approach US levels of obesity within 15 years of moving to America.

The researchers also did an experiment that measured whether or not the threat of appearing un-American influenced respondents' food choices. After being questioned about their ability to speak English 75 percent of Asian-Americans identified a typical American food as their favorite. Only 25 percent of Asian-Americans who had not been asked if they spoke English did the same.

    When their American identity was called into question during a follow-up study, Asian-American participants also tended to choose typical American dishes, such as hamburgers and cheese sandwiches.  In that experiment, 55 Asian-Americans were asked to choose a meal from a local Asian or American restaurant. Some participants were told that only Americans could participate in the study. Those who chose the more typical American fare ended up consuming an extra 182 calories,  including 12 grams of fat and 7 grams of saturated fat (饱和脂肪).

    "People who feel like they need to prove they belong to a culture will change their habits in an attempt to fit in," said Sauna Cheryan, an author of the study and assistant professor of psychology at the University of Washington.

    "If immigrants and their children choose unhealthy American foods over healthier traditional foods across their lives, this process of fitting in could lead to poorer health." Cheryan added.

    Social pressures, the study concluded, are at the heart of the problem.  "In American society today, being American is associated with being white. Americans, who don't fit this image even if they were born here and speak English, feel that pressure to prove that they're American," said Cheryan.

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    Close your eyes for a minute and imagine what life would be like if you had a hundred dollars less. Also imagine what it would be like spending the rest of your life with your eyes closed. Imagine having to read this page, not with your eyes but with your finger-tips.

    With existing medical knowledge and skills, two-thirds of the world's 42 million, blind should not have to suffer. Unfortunately, rich countries possess most of this knowledge, while developing countries do not.

    ORBIS is an international non-profit organization which operates the world's only flying teaching eye hospital. ORBIS intends to help fight blindness worldwide. Inside a DC-8 aircraft, there is a fully-equipped teaching hospital with television studio and classroom. Doctors are taught the latest techniques of bringing sight back to people there. Project ORBIS also aims at promoting peaceful cooperation among countries.

    ORBIS tries to help developing countries by providing training during three-week medical programs. ORBIS has taught sight-saving techniques to over 3,000 doctors and nurses, who continue to cure tens of thousands of blind people every year. ORBIS has conducted 17 plan programs in China so far. For the seven to ten million blind in China ORBIS is planning to do more for them. At the moment an ORBIS is working on a long-term plan to develop a training center and to provide eye care service to Shanxi Province. ORBIS needs your help to continue their work and free people from blindness.

    For just US$38, you can help one person see; for $380 you can bring sight to 10 people; $1,300 helps teach a doctor new skills; and for $13,000 you can provide a training program for a group of doctors who can make thousands of blind people see again. Your money can open their eyes to the world. Please help ORBIS improve the quality of life for so many people less fortunate than ourselves.

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    Misael is three times the size of other children at his age due to a symdrome(综合症 状) which means he is unable to stop eating.

    He is so heavy that he often stops breathing while sleeping — leaving his parents fearing that one day he may not wake up. His dad Manoel Abreu, 38, said, "Everything is hard for him — he is a baby carrying an adult's weight. His heart must be working under a lot of pressure. If he doesn't get the treatment he requires, there is a very good chance that he will pass away."

    Miseal, from Sanot, Brazil, was born a healthy 6lb 6oz, but immediately he started piling on the pounds. Doctors believe he may be suffering from Prader-Willi symdrome, a rare genetic condition that leaves him with greed. He now weighs a heavy 178lb and is still gaining despite following a low-fat diet and walking for 40 minutes each day.

    Mum Josiane, 37, said, "He has been putting on a lot of weight since he was a baby—even when I was breastfeeding him. But it was only when he was one and a half years old that we began to worry. He was gaining 3kg a month and was starting to get very heavy. We know we could lose him at any time. Sometimes when he is sleeping, I watch him to see if he is breathing. I cry a lot because we want to help him. But I am also very proud of him because he doesn't surrender(投降)."

    Misael visits a doctor every three months to try to control his condition, but currently there is no cure for Prader-Willi symdrome. Paediatric neurologist(儿科神经科专家)

    Lucio said, "Every time we meet, he has put on a lot of weight — sometimes up to 5 kg. I think Misael could get help from someone outside Brazil — both medically and financially — so that he can get the laboratory and genetic testing he needs."

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    Food experts say washing could spread the germs on your turkey in the kitchen sink or nearby food. But it's been a challenge trying to convince cooks to stop rinsing (冲洗)off raw poultry. Germs that can make people sick are common in the guts of healthy poultry and are legally allowed to be on raw turkey and chicken. The assumption is that nobody eats their poultry raw, and that thorough cooking will kill the bacteria.

    The do — not — wash raw poultry advice from the USDA is relatively new and perhaps hasn't caught on because it goes against the common belief that washing makes things clean, said Chapman. Benjamin Chapman, a study author and food safety expert at North Carolina State University, said the instinct to wash raw poultry goes back at least decades when people relied more on visual clues to spot problems with poultry. Meanwhile, washing hands and surfaces are also important.

    But food preparation is a complicated act, and germs from poultry can be spread even if it's not washed, especially when birds are removed from packaging.

    The USDA-funded study stresses that point. Researchers sprayed raw chicken with a harmless strain of E. coli (大肠杆菌)and watched volunteer cooks at test kitchens. Among those who washed their raw chicken, about a quarter ended up spreading the bacteria to their lettuce. But even some of those who did not rinse the chicken got germs on the lettuce. And there are other opportunities for germs to survive on turkeys: melting and cooking.

    To ensure a bird is thoroughly cooked, they say to use a thermometer to check that the deepest and thickest parts of it have reached 165 degrees. Even after the meal is cooked, you aren't out of the danger zone. To keep turkeys and other leftovers safe, experts say they should be refrigerated after two hours.

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    Death rates for heart disease in Britain have dropped by more than 40 percent in a decade, UK scientists will report today.

    Wide uptake of cholesterol­busting station drugs(降胆固醇药), healthier lifestyles and better medical practices have seen a huge reduction in deaths caused by heart attacks, stroke and other cardiovascular(心血管的)problems.

    However, heart disease remains Britain's biggest killer.

    The new study, by experts at Oxford University, shows there has been a 44. 4 percent drop in death rates among men in the UK and a 43. 6 percent drop among women linked to heart problems in the ten years to 2011.

    The team compared death rate associated with cardiovascular disease across Europe. They found that Britain has one of the best records in Europe, with 342 deaths as a result of heart disease per 100,000 men in 2011, and 232 per 100, 000 women.

    Some nations—including Ukraine, Macedonia and Moldova—see more than 1,000 heart deaths per 100,000 of the population.

    Overall, heart disease causes 45 percent of all deaths across Europe, but only 27 percent in the UK. The study, led by Dr. Nick Townsend, showed that cardiovascular disease is mainly a disease of old age.

    But researchers said that across Europe it still causes more than 1. 4 million deaths in those aged under 75 and nearly 700,000 deaths in under 65s. Dr. Townsend said: "Cardiovascular disease results in 49 percent of deaths among women and 41 percent among men."

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    Are you wondering whether it's worth going for a little jog? Don't hesitate, and get your sports shoes on. A new study shows that proper running lowers the risk of death before the normal time.

    In an analysis of 14 previous studies from the US and Denmark, the group of researchers from institutes in Australia and Finland concluded that increasing running participation would probably lead to substantial improvements in population health and longevity. The studies involved 232,149 participants over time periods ranging from 5. 5 to 35 years.

    On the whole, people running any distance were associated with a 27% lower risk of death from all causes than those who did not, the study shows. Running was also related with a 30% and 23% lower risk of death from cardiovascular (心血管的) disease and cancer, respectively.

    Previous studies had concluded "inconsistent findings" about whether running could lower the risk of premature death, according to the researchers. Lead researcher Jim White, a professor at Victoria University in Melbourne, told CNN: "Our recent findings may encourage physically inactive individuals to take up running and those who already run to keep on doing it."

    He added that doctors may be encouraged by our findings to promote running as a part of "lifestyle medicine". In their paper, which will be published in the British Journal of Sports Medicine, the researchers say health professionals are sometimes wary of promoting running because vigorous(剧烈的)use of it has been linked with sudden heart death.

    Jim and his team deny this by noting that the benefit of running outweighs the risk. However, they did say advice should be given on a case-by-case basis, as running might not be appropriate for everyone. Although running has a clear health benefit, the researchers point out that higher "doses" of running may not reduce the risk of premature death further. According to the WHO's guidelines, adults aged between 18 and 64 should take 150 minutes of gentle exercise or 75 minutes of vigorous exercise each week.

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    More primary care doctors in a community (社区) appear to lead to improved life expectancy for people living there，though a lack of such physicians across U.S. could be a cause of concern for overall population health in years to come.

    For the study, researchers looked at physician counts per 100,000 people in a range covering 2005 to 2015 in the U. S.，along with life expectancy and specific causes of death. They found that an increase of 10 primary care physicians per 100,000 population was associated with a 51. 5-day increase in life expectancy, while an increase of 10 specialty physicians per 100, 000 population increased life expectancy by 19. 2 days. An increase in primary care physicians also was associated with reductions of many deaths including heart diseases and cancers.

    Along with those findings, though, the study said many communities did not have primary care physicians in 2015，with the decline in supply more prominent in rural areas than their urban areas. Many believe that a well-functioning health care system requires a solid foundation of primary care, however, payment difference between primary care and technical specialties continue to dispirit the U. S. primary care physician workforce.

    “Higher pay and lifestyle preferences lead most students to choose non-primary care fields, even when their hearts say primary care,” the study said. “We must turn this trend around with practical changes in physician payment policy; no amount of superb primary care training or creative practice reform will prevent further declines in primary care physician, which will lead to worsening health for the United States. ”

    The study's researchers conclude that future research should focus on the “quality and cover of primary care，types of primary care physician training and service offerings, and effective access rather than just supply”.

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From talking robots to driverless vehicles, technology has become so advanced that the previously impossible seems to occur on a daily basis. And yet-we still have no cure for the common cold.

Why can't we stop the common cold? According to Peter Barlow, a scientist at Edinburgh Napier University, the main challenge lies in the many different types of cold viruses that belong to the rhinoviruses(鼻病毒). There are at least 160 types. They mutate(突变) so easily that they quickly become resistant to drugs, or learn to hide from our immune systems. In other words, a single cure isn't likely to work on every type of cold.

However, researchers from Stanford University and the University of California, San Francisco, have found a possible answer. They discovered a protein(蛋白质) that the viruses need. All the viruses were unable to replicate(复制) inside cells without a gene that produces a specific protein called SETD3.

To identify the gene which produces the specific protein, researchers used a gene-editing technique to test all genes in the human genome (基因组). Namely, they randomly disabled a single gene in each of the cells, so that the cells lacked one or another of every gene in our genome. These genetically modified cells were then exposed to the rhinoviruses, which cause the common cold. The team then looked at which gene was missing in cells that continued to grow. As it turned out, the one that stood out was SETD3, which makes a protein of the same name.

Carette said the plan is to find a drug which can temporarily disable the protein, instead of producing genetically modified humans. "We have identified a fantastic target that all rhinoviruses require and depend on. Take that away and the virus really has no chance," said Carette.

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Healthy Habits, Healthy Body

Feel tired lately? Has a doctor said he can't find anything wrong with you？ Perhaps he sent you to a hospital, but all the advanced equipment there shows that there is nothing wrong with you.

Then, consider this: you might be in a state of subhealth(亚健康).

Subhealth, also called the third state or gray state, is explained as a borderline state between health and disease.

According to the investigation by the National Health Organization, over 45 percent of subhealthy people are middle­aged or elderly. The percentage is even higher among people who work in management positions as well as students around exam weeks.

Symptoms(症状) include a lack of energy, depression (压抑), slow reactions, insomnia (失眠), agitation, and poor memory. Other symptoms include shortness of breath, sweating and aching in the waist and legs.

The key to preventing and recovering from subhealth, according to some medical experts, is to form good living habits, alternate work and rest, exercise regularly, and take part in open­air activities.

As for meals, people are advised to eat less salt and sugar. They should also eat more fresh vegetables, fruit and fish because they are rich in nutritional elements－vitamins and trace elements that are important to the body.

Nutrition(营养) experts point out that it is not good to eat too much at one meal because it may cause unhealthy changes in the digestive tract(消化系统). They also say that a balanced diet is very helpful in avoiding subhealth.

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World Health Organization (WHO) chief scientist Soumya Swaminathan said Monday that herd immunity to coronavirus would not be achieved in 2021, despite the growing availability of vaccines (疫苗产量).

Factors that delay herd immunity include limited access to vaccines in developing countries, skepticism (怀疑) over vaccination, and the potential for virus mutations (变异), according to health experts.

A growing number of countries around the world, including the United States, the United Kingdom, Singapore, Germany and other European Union countries, are in the first stages of mass-vaccination campaigns.

Herd immunity occurs when enough people in a population have immunity to an infection(传染) so that it prevents the disease from spreading.

"We are not going to achieve any levels of population immunity or herd immunity in 2021," Swaminathan said, while emphasizing that measures like physical distancing, hand washing and mask wearing continue to be necessary in controlling COVID's spread for the rest of the year.

However, Swaminathan praised the "incredible progress" made by vaccine researchers to develop several safe and effective vaccines at unprecedented (空前的) speed. Countries are currently administering vaccines developed by BioNTech-Pfizer, Oxford University AstraZeneca and Moderna.

"The vaccines are going to come," she said. "They are going to go to all countries, but meanwhile we mustn't forget that there are measures that work," she added, referring to hygiene (卫生) and social distancing.

"We won't get back to normal quickly," Dale Fisher, chairman of the WHO's Outbreak Alert and Response Network, told a conference hosted by Reuters news agency. "We know we need to get to herd immunity and we need that in a majority of countries, but we are not going to see that in 2021," Fisher said. "There might be some countries that might achieve it but even then that will not create normal especially in terms of border controls," he added.

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How do you like your milk: cooked or raw? It may sound a strange question, but it's being asked more often at kitchen tables, grocery stores and farmers' markets across the US.

The vast majority of milk we drink is heat-treated to kill off harmful bacteria (细菌). Raw milk, on the other hand, goes straight to bottle. Fans call it milk as nature intended: nutrient-rich and full of a good kind of bacteria. Some fans go further, calling it a super food that aids digestion (消化), benefits the immune system and treats some diseases.

An increasing number of people agree. For health-conscious, organic-loving shoppers, raw milk is a growing food trend. They feel uneasy at the thought of heated milk sitting under supermarket lighting. But despite the enthusiasm, it's a trend with a terrible side.

Pasteurization (加热杀菌) is a reason—it's highly effective at killing some harmful things that can hang around in the body of even healthy cows. Raw milk, on the other hand, relies heavily on the skill of the farmer to avoid them.

Raw milk illnesses have increased as more people drink it. Between 2010 and 2019, raw milk and raw milk cheese caused the vast majority (96%) of all illnesses linked to dairy products. Considering far fewer people consume it, that makes unpasteurized dairy 840 times more risky than pasteurized. The recent deaths of two people who ate raw milk cheese made in New York underscored the sometimes deadly consequences. And for young children, whose underdeveloped immune systems make them more vulnerable (易受伤害的), the dangers of raw milk make it hard to recommend.

For each blank in the following passage there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.

In 1965, 17-year-old high school student Randy Gardner stayed awake for 264 hours to see how he'd cope without sleep. On the second day, his eyes stopped focusing. Next, he lost the ability to 1 objects by touch. By day three, Gardner was moody and uncoordinated. At the end of the experiment, he was 2 to concentrate, had trouble with short-term memory and started hallucinating(出现幻觉). Although Gardner recovered without long-term psychological or physical 3, for others, sleeplessness can result in hormone(激素) imbalance, illness, and even death.

Sleep is 4. Adults need 7 to 8 hours of sleep at night, and adolescents need about 10. In the United States, it's estimated that 30% of adults and 66% of adolescents are 5 sleep deprived. When we lose sleep, learning, memory, mood, and reaction time are affected. Sleeplessness may also cause inflammation, hallucinations, high blood pressure, and it's even been 6 to diabetes and obesity.

How can sleep 7 cause such enormous suffering? Scientists think the answer lies with the 8 of waste products in the brain. During our waking hours, our cells are busy using up our day's energy sources which get broken down into various by-products, including adenosine(腺苷酸). As adenosine builds up, it increases the 9 to sleep, also known as sleep pressure. In fact, caffeine works by 10 adenosine's receptor pathways. Other waste products also build up in the brain, and if they're not cleared away, they collectively 11 the brain and are thought to lead to the many negative symptoms of sleep deprivation.

So, what's happening in our brain when we sleep, to prevent this? Scientists found something called the Lymphatic System, a clean-up mechanism(机能) that removes this build-up and is much more 12 when we're asleep. It works by using cerebrospinal fluid(脑脊髓液) to flush away toxic by-products that accumulate between cells. Lymphatic vessels, which 13 pathways for immune cells, have recently been discovered in the brain, and they may also play a role in 14 the brain's daily waste products. While scientists continue exploring the restorative mechanisms behind sleep, we can be sure that sleeping is a(n) 15 if we want to maintain our health and our sanity.