单选题 For years, doctors advised their patients that the only thing taking multivitamins does is give them extensive urine(尿). After all, true vitamin deficiencies are practically unheard of in industrialized countries. Now it seems that those doctors may have been wrong. The results of a growing number of studies suggest that even a modest vitamin shortfall can be harmful to your health. Although proof of the benefits of multivitamins is still far from certain, the few dollars you spend on them is probably a good investment. Or at least that's the argument put forward in the New England Journal of Medicine. Ideally, said Dr. Walter Willett and Dr. Meir Stampfer of Harvard, all vitamin supplements would be evaluated in scientifically rigorous clinical trials. But those studies can take a long time and often raise more questions than they answer. At some point, while researchers work on figuring out where the truth lies, it just makes sense to say the potential benefit outweighs the cost. The best evidence to date concerns folate(叶酸), one of the B vitamins. It's been proved to limit the number of defects in embryos(胚胎), and a recent trial found that folate in combination with vitamin B12 and a form of B6 also decreases the re-blockage of arteries after surgical repair. The news on vitamin E has been more mixed. Healthy folks who take 400 international units daily for at least two years appear somewhat less likely to develop heart disease. But when doctors give vitamin E to patients who already have heart disease, the vitamin doesn't seem to help. It may turn out that vitamin E plays a role in prevention but cannot undo serious damage. Despite vitamin C's great popularity, consuming large amounts of it still has not been positively linked to any great benefit. The body quickly becomes saturated with C and simply excretes(排泄)any excess. The multivitamins question boils down to this: Do you need to wait until all the evidence is in before you take them, or are you willing to accept that there's enough evidence that they don't hurt and could help? If the latter, there's no need to go to extremes and buy the biggest horse pills or the most expensive bottles. Large doses can cause trouble, including excessive bleeding and nervous system problems. Multivitamins are no substitute for exercise and a balanced diet, of course. As long as you understand that any potential benefit is modest and subject to further refinement, taking a daily multivitamin makes a lot of sense.
单选题 At one time doctors discouraged taking multivitamins because they believed that multivitamins ______.
【正确答案】 A
【答案解析】解析：细节推理题。文章首句提及多年以来，医生们建议病人们摄人多种维生素，只会导致他们多尿，由此可知，对于医生来说，维生素不易被身体吸收，只会被排出体外。选项A与此信息一致。故答案为A
单选题 According to the author, clinical trials of vitamin supplements______.
【正确答案】 B
【答案解析】解析：事实细节题。文章第二段提及所有的维生素供应都会在实验的基础上进行科学的评估，之后第三段提及But those studies can take a long time and often raise more questions than they answer，选项B与此信息一致。故答案为B。
单选题 It has been found that vitamin E______.
【正确答案】 C
【答案解析】解析：事实细节题。文章第三段提及“It may turn out that vitamin E plays a role in prevention but cannotundo serious damage”，选项C中提及维生素对于心脏病的作用——preventive but not curative effect，与文章内容一致。故答案为C。
单选题 It can be seen that large doses of multivitamins______.
【正确答案】 A
【答案解析】解析：事实细节题。文章倒数第二段末句提及过量的服用会造成一些问题(can cause trouble)，包括流血不止和神经系统方面的问题(including excessive bleeding and nervous system problems)。选项A中serious side effects(严重的副作用)与文章信息对应。故答案为A。
单选题 The author concludes the passage with the advice that______.
【正确答案】 D
【答案解析】解析：事实细节题。文章末段提及对于维生素，大众应采取的态度：潜在的好处都不会太大(modest)，但是会带来长久的好处(subject to further refinement)，日常摄入维生素对身体是很有好处的(taking a daily multivitamin makes a lot of sense)，选项D与文章意义一致。故答案为D。