Passage 3

For years，doctors advised their patients that the only thing taking multivitamins does is give them expensive urine（尿）.After all，true vitamin deficiencies are practically unheard of in industrialized countries.Now it seems 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，say 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，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.

1.At one time doctors discouraged taking multivitamins because they believed that multiv-itamins______.

A.could not easily be absorbed by the human body

B.were potentially harmful to people’s health

C.were too expensive for daily consumption

D.could not provide any cure for vitamin deficiencies

2.According to the author，clinical trials of vitamin supplements______.

A.often result in misleading conclusions

B.take time and will not produce conclusive results

C.should be conducted by scientists on a larger scale

D.appear to be a sheer waste of time and resources

3.It has been found that vitamin E______.

A.should be taken by patients regularly and persistently

B.can effectively reduce the recurrence of heart disease

C.has a preventive but not curative effect on heart disease

D.should be given to patients with heart disease as early as possible

4.It can be seen that large doses of multivitamins______.

A.may bring about serious side effects

B.may help prevent excessive bleeding

C.are likely to induce the blockage of arteries

D.are advisable for those with vitamin deficiencies

5.The author concludes the passage with the advice that______.

A.the benefit of daily multivitamin intake outweighs that of exercise and a balanced diet

B.it’s risky to take multivitamins without knowing their specific function

C.the potential benefit of multivitamins can never be overestimated

D.it’s reasonable to take a rational dose of multivitamins daily

参考译文

多年来，医生提醒病人，服用多种维生素唯一能带给他们的就是昂贵的尿液。毕竟，在工业国家，真正意义上的维生素缺乏实际上闻所未闻。不过现在看来那些医生可能错了。大量研究结果显示，即使少量的维生素短缺也会损害健康。尽管多种维生素的益处还不能确定，但花上几美元购买它们可能是一个不错的投资。

或者，这起码是《新英格兰医药杂志》提出的论断。哈佛大学的Walter Willett和Meir Stamper博士指出，理想状况下，所有的维生素补充剂都要经过严格的、科学的临床试验评估。但这些研究耗时很长，而且它们带来的问题比解决的要多。有时候，当研究者努力找出真相时，也只能说潜在的利益要超过其成本。

到目前为止，一个很好的例子是叶酸，它是维生素B的一种。它被证明能限制胎盘的缺陷，而且最近的试验发现，叶酸和维生素B12及一种B6共同使用时，能降低外科手术后动脉的再次阻塞。

关于维生素E的新闻则复杂得多。每天服用400国际单位维生素E至少两年的健康人群，得心脏病的可能性要比常人小。但是医生给已患心脏病的病人服用维生素E时，却似乎没有任何帮助。这表明维生素E在预防中能起到作用，但无法治疗严重的损伤。

尽管服用维生素C相当普遍，但始终不能肯定大量服用维生素C是否一定会有很大的益处。因为体内的维生素C迅速饱和后，多余部分就会完全被排出体外。

现在多种维生素的问题可以归结为：你需要等到所有的证据证明它们有用时才开始服用，还是愿意在现有证据足以证明它们无害而且可能带来好处时服用？

如果是后者，那就没有必要走极端，去买最大剂量的药片或者最贵的药品。因为大剂量会带来包括出血过多和神经系统疾病的麻烦。

当然，多种维生素不是运动和平衡饮食的替代品。只要你明白任何潜在的益处都是有限的而且需要进一步细化，每天服用多种维生素就很有意义了。

解题之路

1.选A。本题问医生曾经不鼓励服用多种维生素的原因。根据题干中的At one time和doctors可以定位到文章第一段的第一句，意思是多年来医生忠告他们的病人，服用多种维生素的唯一作用是排泄昂贵的尿。句子主干是doctors advised their patients，that引导主语从句。言外之意是，花了钱却排泄掉了，正符合A.could not easily be absorbed by the human body不能轻易地被身体所吸收，属于概括性替换。B.were potentially harmful to people’s health对人的身体有潜在的危害，原文无信息支持；C.were too expensive for daily consumption对于日常消费是太昂贵了，是曲解原文，原文中的expensive是修饰的尿而不是维生素，只是说明花钱服用后排泄掉了，是一种浪费。这个选项有很大的迷惑性；D.could not provide any cure for vitamin deficiencies不能对维生素缺乏症提供任何治疗，利用第二句中的vitamin deficiencies来干扰考生。

2.选B。本题针对维生素补剂的临床实验提问。根据题干中的clinical trials可以定位到文章第二段。第三句的意思是，这些实验研究耗费时间长，而且所引起的疑问要比能够回答的疑问多。所以选B.take time and will not produce conclusive results花费时间而且产生的结果不确定。A.often result in misleading conclusions经常导致误导性的结论，错在misleading无信息支持；C.should be conducted by scientists on a larger scale应该由医生更大规模地进行，也无信息支持；D.appear to be a sheer waste of time and resources看起来是纯粹浪费时间和资源，无信息支持，说得太绝对。

3.选C。根据关键词vitamin E定位到第四段。考生对阅读文章中出现的某个概念要及时做标记，根据前面对段落的分析，应该选C.has a preventive but not curative effect on heart disease有预防但没有治愈心脏病的效果。A.should be taken by patients regularly and persistently应该有规律并且坚持被病人所服用；B.can effectively reduce the recurrence of heart disease能够有效地减少心脏病的复发；D.should be given to patients with heart disease as early as possible应该被尽早地给予患心脏病的人。这三个干扰项均无信息支持。本题只要定位准确，应该很容易解答。

4.选A。本题问从文章中可以看出服用大剂量的多种维生素会怎样，根据题干中的large doses of multivitamins可以定位到文章第七段的第二句，大剂量的服用可能会引起麻烦，例如失血过多或造成神经系统的问题。所以应该选A.may bring about serious side effects可能会引起严重的副作用。side effects是对原文中excessive bleeding and nervous system problems的概括性替换。B.may help prevent excessive bleeding可能有助于帮助防止失血过多，与原文说法相反；C.the likely to induce the blockage of arteries可能会引起动脉堵塞，文中无信息支持；D.are advisable for those with vitamin deficiencies对于那些维生素缺乏的人是可取的，也无信息支持。

5.选D。本题问作者用一个什么建议来总结全文的，最后一段的意思：当然，多种维生素不能代替锻炼和平衡的饮食。只要对此理解了，就应知道选D.it’s reasonable to take a rational dose of multivitamins daily每日服用合理的剂量是明智的。A.the benefit of daily multivitamin intake outweighs that of exercise and a balanced diet与文章最后一段的第一句相反；B.it’s risky to take multivitamins without knowing their specific function在不知道维生素具体的功能之前就服用是危险的，这不仅不是作者的建议，而且与原文第六段的说法不一致；C.the potential benefit of multivitamins can never be overestimated维生素的潜在好处再高估也不过分，这也不是作者的建议。

词汇精解

multivitamin n.多种维生素

deficiency n.缺乏，不足，缺陷

advise vt.劝告，忠告，警告，建议

expensive adj.昂贵的

urine n.尿

proof n.试验，考验，证据

benefit n.利益，好处

clinical adj.临床的

trial n.审讯，考验，试验

outweigh vt.（在重量或价值方面）超过

popularity n.普及，声望，盛行

consume vt.消耗，消灭，消费

positively adv.断然地，肯定地

evidence n.迹象，根据，证据

practically adv.事实上，实际上

industrialized adj.工业化的

shortfall n.不足，缺乏

investment n.可获利的东西，投资

potential adj.可能的，潜在的

supplement n.补遗，附录，补充

evaluate vt.评价，评估

rigorous adj.严厉的，严酷的，严峻的，严格的

in adj.在里面的，执政的，已来到的

take vt.拿，取，占领，服（药）

extreme n.极端，极端的事物

help vi.救命，招待，起作用

latter adj.后面的，（两者中）后者的

modest adj.谦虚的，谦让的，适度的

refinement n.精致，精巧，提炼

daily adv.每日，天天，每天地

难句解析

1.For years，doctors advised their patients that the only thing taking multivitamins does is give them expensive urine.

【参考译文】多年来，医生提醒病人，服用多种维生素唯一能带给他们的就是昂贵的尿液。

【结构分析】这是一个主从复合句，可以切分为：（For years，doctors advised their patients）（that the only thing//taking multivitamins does//is give them expensive urine）。第一部分是主干，即主谓宾结构，For years是时间状语；第二部分是that引导的从句，作advised的直接宾语，其主干是the only thing…is…，不定式give…urine作表语，give之前省略了to，一般而言，不定式作表语时，如果be动词之前有实义动词do，则不定式的to可省，taking…does是the only thing的定语从句，taking是动名词，作主语，does是谓语动词。

【知识链接】for years多年来；advise sb.that建议某人……

2.Although proof of the benefits of multivitamins is still far from certain，the few dollars you spend on them is probably a good investment.

【参考译文】尽管多种维生素的益处还不能确定，但花上几美元购买它们可能是一个不错的投资。

【结构分析】这是一个主从复合句，可以切分为：（Although proof of the benefits of multivitamins is still far from certain），（the few dollars//you spend on them//is probably a good investment）。第一部分是Although引导的让步状语从句，即主系表结构；第二部分是主句，主语是the few dollars，谓语是is，表语是a good investment，分隔号内是the few dollars的定语从句，them指代前面的multivitamins。

【知识链接】be far from远非……；spend…on…花（钱）做……

3.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.

【参考译文】有时候，当研究者努力找出真相时，也只能说潜在的利益要超过其成本。

【结构分析】这是一个主从复合句，可以切分为：（while researchers work on figuring out//where the truth lies//），（it just makes sense to say//the potential benefit outweighs the cost//）。第一部分是while引导的时间状语从句，work on是谓语，之后的动名词结构figuring out…是其宾语，分隔号内where引导的是figuring out的宾语从句；第二部分是主句，主语it指代后面的不定式to say…the cost，分隔号内the potential…cost是say的宾语从句。

【知识链接】at some point有时；work on从事；figure out弄清楚；make sense有道理

4.Despite vitamin C’s great popularity，consuming large amounts of it still has not been positively linked to any great benefit.

【参考译文】尽管服用维生素C相当普遍，但始终不能肯定大量服用维生素C是否一定会有很大的益处。

【结构分析】这是一个简单句，Despite…popularity是让步状语，动名词短语consuming…it是主语，谓语是has not been…linked，介词短语to any great benefit是方向状语。

【知识链接】large amounts of大量；be linked to与……有关

5.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？

【参考译文】你需要等到所有的证据证明它们有用时才开始服用，还是愿意在现有证据足以证明它们无害而且可能带来好处时服用？

【结构分析】这是由or连接的并列句，可以切分为：（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？//）。第一部分的两个分隔号内until…in和before…them均是时间状语从句，其中的in是形容词；第二部分的第一个分隔号内是that引导的从句，作accept的宾语，第二个分隔号内的从句是evidence的同位语。

【知识链接】need to do有必要……；sth.is in很流行的，已来到的；be willing to do乐于做……

6.If the latter，there’s no need to go to extremes and buy the biggest’horse pills or the most expensive bottles.

【参考译文】如果是后者，那就没有必要走极端，去买最大剂量的药片或者最贵的药物。

【结构分析】这是一个主从复合句，If引导的条件状语从句中出现了省略现象，补全后应是：If（it is）the latter；主句中的不定式to go…and buy…bottles是need的后定语。

【知识链接】there’s no need to do没有必要做……；go to extremes走极端；horse pill大片（药）

7.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.

【参考译文】只要你明白任何潜在的益处都是有限的而且需要进一步细化，每天服用多种维生素就有意义了。

【结构分析】这是一个主从复合句，As long as引导条件状语从句，that引导的是understand的宾语从句，该从句的主语是any potential benefit，谓语是is，表语是modest and subject to，further refinement是介词to的宾语；主句的主语是动名词短语taking a daily multivitamin。

【知识链接】as long as只要（引导条件状语从句）；be subject to应该……；make a lot of sense很有意义