题目

已知偶函数在区间上单调递增，则满足的的取值范围为（）A. B. C. D. 答案：【答案】A【解析】根据单调性，将函数值的大小关系转变为自变量间的大小关系，注意偶函数对应的函数的对称情况.因为偶函数是在上递增，则在递减，且；又因为，根据单调性和奇偶性有：，解得：,故选：A.Drinking a lot of water does not do any good to the body, according to two experts in the United States. In fact, they warn, drinking too much water could be, in certain cases, harmful.In a study, Dr Stanly Goldfarb and Dr Dan Negoianu, both of the Renal, Electrolyte and Hypertension Division at the University of Pensylvania, the United States, have denied the popular belief that drinking a lot of water clears body toxins（毒素）better, improves skin, and helps reduce weight.Dr Goldfarb and Dr Negoianu say that they found little proof to back the public opinion that drinking 8 glasses of water every day benefits health. At the same time, they fond little proof of harm in drinking 8 glasses of water every day.It is widely believed that in some cases-such as athletes, people who live in hot, dry environments, and those with certain medical conditions-drinking a lot of water indeed helps, but no studies have been done to prove the benefits of this practice in average, healthy people, the website medheadlines.com reports.The study at the University of Pennsylvania also examined reports that some people experienced increased headaches when their consumption（消耗）of water was low. In one small study, which the doctors reviewed, the group drinking the most water reported fewer headaches than the control group, “but the difference in the number of headaches was o small between the two groups as to be considered unimportant.”The researchers concluded that there is no scientific proof to support that average, healthy people need to drink at least 8 glasses of water each each day.The website medheadines.com says that, according to an Indian doctor, drinking too much water is harmful. If water enters the body more quickly than it can be removed, problems can occur1.What’s the key message delivered in the passage?A.Drinking too much water might bring harmB.Whether to drink enough water makes no differenceC.Drinking too much water may cause headachesD.Average, healthy people should drink more water2.We can learn from the passage that 8 glasses of water every day_______A.proves good for the bodyB.has scientific proof of harmC.is sure to reduce headachesD.is generally considered necessary3.Who may agree that drinking lots of water helps to lose weight?A.The two expertsB.The Indian doctorC.The general publicD.The website4.According to the passage, we know that_______A.the website medheadlnes.com is developed by an Indian doctorB.the study was carried out by two experts with an Indian doctorC.the two experts performed the study at the University of PennsylvaniaD.drinking 8 glasses of water every day can cure certain diseases