题目

桦尺蛾是一种栖息在密林中、白天停歇在树干上的昆虫，一般为浅色，它借助与环境相似的体色躲避鸟类天敌。在工业污染区，黑色花尺蛾的数量有增多的趋势。为证实两种体色的桦尺蛾因环境不同而数量比例不同，进行了如下探究。请完成下列探究方案。 （1）假设：_____________________________________________。 （2）实验步骤： 1）选择工业污染区A和_____________________地区B；  2）收集桦尺蛾，并在翅下用有色颜料分别标记黑色蛾和浅色蛾若干； 3）_____________Perhaps everyone has heard warnings about the “freshman 15”, but is it true that many college students weigh 15 pounds more during their first year at school?Recent studies find that some first-year students are indeed likely to gain weight, but it might not be the full freshman 15, and it may not all happen during the freshman year. That might sound like good news, but it’s not. Doctors are concerned that students who gradually put on pounds could have healthy problems.Studies show that students on average gain 3-10 pounds during their first 2 years of college. Most of this weight gain occurs during the first year. A college offers many temptations (诱惑). You’re on your own and free to eat what you want. In addition, you may not get as much exercise as you did in high school. A college is also a time of change, and people sometimes eat in response to (对……做出反应) homesickness, sadness, or stress, and all of these can be part of starting a new life in college.Some weight gain is normal as a young body grows, but rapid weight gain may become a problem. Weight gain that pushes you above the body’s normal range carries health risks. People who are overweight are more likely to have high blood pressure, heart disease and develop certain cancers.The best way to beat “freshman 15” is to prevent it altogether. Good habits like a balanced diet, regular exercise, and getting enough sleep can do more than keeping the pounds off. They can also help you stay healthy.1.The “freshman 15” refers to the fact that the first-year college students ________. A.are likely to gain much weight   B.can’t get used to living in collegeC.may have 15 health problems   D.gradually put on weight in 15 weeks2.According to the writer, the causes of “freshman 15” don’t include ________. A.getting less exercise         B.being free to eat foodC.feeling homesick           D.having more subjects.3.What is the best way to beat “freshman 15”? A.To ask doctors for advice.       B.To pay attention to your lessons.C.To stop it from happening.       D.To do a lot exercise every day.4.What can we learn from the text? A.Getting less sleep can help people lose weight gradually.B.Overweight people usually have more health risks.C.Weight gain is becoming serious among college students.D.Students gain more weight in the second year than in the first.