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

參考譯文

多年來，醫(yī)生提醒病人，服用多種維生素唯一能帶給他們的就是昂貴的尿液。畢竟，在工業(yè)國家，真正意義上的維生素缺乏實際上聞所未聞。不過現(xiàn)在看來那些醫(yī)生可能錯了。大量研究結(jié)果顯示，即使少量的維生素短缺也會損害健康。盡管多種維生素的益處還不能確定，但花上幾美元購買它們可能是一個不錯的投資。

或者，這起碼是《新英格蘭醫(yī)藥雜志》提出的論斷。哈佛大學的Walter Willett和Meir Stamper博士指出，理想狀況下，所有的維生素補充劑都要經(jīng)過嚴格的、科學的臨床試驗評估。但這些研究耗時很長，而且它們帶來的問題比解決的要多。有時候，當研究者努力找出真相時，也只能說潛在的利益要超過其成本。

到目前為止，一個很好的例子是葉酸，它是維生素B的一種。它被證明能限制胎盤的缺陷，而且最近的試驗發(fā)現(xiàn)，葉酸和維生素B12及一種B6共同使用時，能降低外科手術(shù)后動脈的再次阻塞。

關(guān)于維生素E的新聞則復雜得多。每天服用400國際單位維生素E至少兩年的健康人群，得心臟病的可能性要比常人小。但是醫(yī)生給已患心臟病的病人服用維生素E時，卻似乎沒有任何幫助。這表明維生素E在預(yù)防中能起到作用，但無法治療嚴重的損傷。

盡管服用維生素C相當普遍，但始終不能肯定大量服用維生素C是否一定會有很大的益處。因為體內(nèi)的維生素C迅速飽和后，多余部分就會完全被排出體外。

現(xiàn)在多種維生素的問題可以歸結(jié)為：你需要等到所有的證據(jù)證明它們有用時才開始服用，還是愿意在現(xiàn)有證據(jù)足以證明它們無害而且可能帶來好處時服用？

如果是后者，那就沒有必要走極端，去買最大劑量的藥片或者最貴的藥品。因為大劑量會帶來包括出血過多和神經(jīng)系統(tǒng)疾病的麻煩。

當然，多種維生素不是運動和平衡飲食的替代品。只要你明白任何潛在的益處都是有限的而且需要進一步細化，每天服用多種維生素就很有意義了。

解題之路

1.選A。本題問醫(yī)生曾經(jīng)不鼓勵服用多種維生素的原因。根據(jù)題干中的At one time和doctors可以定位到文章第一段的第一句，意思是多年來醫(yī)生忠告他們的病人，服用多種維生素的唯一作用是排泄昂貴的尿。句子主干是doctors advised their patients，that引導主語從句。言外之意是，花了錢卻排泄掉了，正符合A.could not easily be absorbed by the human body不能輕易地被身體所吸收，屬于概括性替換。B.were potentially harmful to people’s health對人的身體有潛在的危害，原文無信息支持；C.were too expensive for daily consumption對于日常消費是太昂貴了，是曲解原文，原文中的expensive是修飾的尿而不是維生素，只是說明花錢服用后排泄掉了，是一種浪費。這個選項有很大的迷惑性；D.could not provide any cure for vitamin deficiencies不能對維生素缺乏癥提供任何治療，利用第二句中的vitamin deficiencies來干擾考生。

2.選B。本題針對維生素補劑的臨床實驗提問。根據(jù)題干中的clinical trials可以定位到文章第二段。第三句的意思是，這些實驗研究耗費時間長，而且所引起的疑問要比能夠回答的疑問多。所以選B.take time and will not produce conclusive results花費時間而且產(chǎn)生的結(jié)果不確定。A.often result in misleading conclusions經(jīng)常導致誤導性的結(jié)論，錯在misleading無信息支持；C.should be conducted by scientists on a larger scale應(yīng)該由醫(yī)生更大規(guī)模地進行，也無信息支持；D.appear to be a sheer waste of time and resources看起來是純粹浪費時間和資源，無信息支持，說得太絕對。

3.選C。根據(jù)關(guān)鍵詞vitamin E定位到第四段?？忌鷮﹂喿x文章中出現(xiàn)的某個概念要及時做標記，根據(jù)前面對段落的分析，應(yīng)該選C.has a preventive but not curative effect on heart disease有預(yù)防但沒有治愈心臟病的效果。A.should be taken by patients regularly and persistently應(yīng)該有規(guī)律并且堅持被病人所服用；B.can effectively reduce the recurrence of heart disease能夠有效地減少心臟病的復發(fā)；D.should be given to patients with heart disease as early as possible應(yīng)該被盡早地給予患心臟病的人。這三個干擾項均無信息支持。本題只要定位準確，應(yīng)該很容易解答。

4.選A。本題問從文章中可以看出服用大劑量的多種維生素會怎樣，根據(jù)題干中的large doses of multivitamins可以定位到文章第七段的第二句，大劑量的服用可能會引起麻煩，例如失血過多或造成神經(jīng)系統(tǒng)的問題。所以應(yīng)該選A.may bring about serious side effects可能會引起嚴重的副作用。side effects是對原文中excessive bleeding and nervous system problems的概括性替換。B.may help prevent excessive bleeding可能有助于幫助防止失血過多，與原文說法相反；C.the likely to induce the blockage of arteries可能會引起動脈堵塞，文中無信息支持；D.are advisable for those with vitamin deficiencies對于那些維生素缺乏的人是可取的，也無信息支持。

5.選D。本題問作者用一個什么建議來總結(jié)全文的，最后一段的意思：當然，多種維生素不能代替鍛煉和平衡的飲食。只要對此理解了，就應(yīng)知道選D.it’s reasonable to take a rational dose of multivitamins daily每日服用合理的劑量是明智的。A.the benefit of daily multivitamin intake outweighs that of exercise and a balanced diet與文章最后一段的第一句相反；B.it’s risky to take multivitamins without knowing their specific function在不知道維生素具體的功能之前就服用是危險的，這不僅不是作者的建議，而且與原文第六段的說法不一致；C.the potential benefit of multivitamins can never be overestimated維生素的潛在好處再高估也不過分，這也不是作者的建議。

詞匯精解

multivitamin n.多種維生素

deficiency n.缺乏，不足，缺陷

advise vt.勸告，忠告，警告，建議

expensive adj.昂貴的

urine n.尿

proof n.試驗，考驗，證據(jù)

benefit n.利益，好處

clinical adj.臨床的

trial n.審訊，考驗，試驗

outweigh vt.（在重量或價值方面）超過

popularity n.普及，聲望，盛行

consume vt.消耗，消滅，消費

positively adv.斷然地，肯定地

evidence n.跡象，根據(jù)，證據(jù)

practically adv.事實上，實際上

industrialized adj.工業(yè)化的

shortfall n.不足，缺乏

investment n.可獲利的東西，投資

potential adj.可能的，潛在的

supplement n.補遺，附錄，補充

evaluate vt.評價，評估

rigorous adj.嚴厲的，嚴酷的，嚴峻的，嚴格的

in adj.在里面的，執(zhí)政的，已來到的

take vt.拿，取，占領(lǐng)，服（藥）

extreme n.極端，極端的事物

help vi.救命，招待，起作用

latter adj.后面的，（兩者中）后者的

modest adj.謙虛的，謙讓的，適度的

refinement n.精致，精巧，提煉

daily adv.每日，天天，每天地

難句解析

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

【參考譯文】多年來，醫(yī)生提醒病人，服用多種維生素唯一能帶給他們的就是昂貴的尿液。

【結(jié)構(gòu)分析】這是一個主從復合句，可以切分為：（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，即主謂賓結(jié)構(gòu)，F(xiàn)or years是時間狀語；第二部分是that引導的從句，作advised的直接賓語，其主干是the only thing…is…，不定式give…urine作表語，give之前省略了to，一般而言，不定式作表語時，如果be動詞之前有實義動詞do，則不定式的to可省，taking…does是the only thing的定語從句，taking是動名詞，作主語，does是謂語動詞。

【知識鏈接】for years多年來；advise sb.that建議某人……

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.

【參考譯文】盡管多種維生素的益處還不能確定，但花上幾美元購買它們可能是一個不錯的投資。

【結(jié)構(gòu)分析】這是一個主從復合句，可以切分為：（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引導的讓步狀語從句，即主系表結(jié)構(gòu)；第二部分是主句，主語是the few dollars，謂語是is，表語是a good investment，分隔號內(nèi)是the few dollars的定語從句，them指代前面的multivitamins。

【知識鏈接】be far from遠非……；spend…on…花（錢）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.

【參考譯文】有時候，當研究者努力找出真相時，也只能說潛在的利益要超過其成本。

【結(jié)構(gòu)分析】這是一個主從復合句，可以切分為：（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引導的時間狀語從句，work on是謂語，之后的動名詞結(jié)構(gòu)figuring out…是其賓語，分隔號內(nèi)where引導的是figuring out的賓語從句；第二部分是主句，主語it指代后面的不定式to say…the cost，分隔號內(nèi)the potential…cost是say的賓語從句。

【知識鏈接】at some point有時；work on從事；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.

【參考譯文】盡管服用維生素C相當普遍，但始終不能肯定大量服用維生素C是否一定會有很大的益處。

【結(jié)構(gòu)分析】這是一個簡單句，Despite…popularity是讓步狀語，動名詞短語consuming…it是主語，謂語是has not been…linked，介詞短語to any great benefit是方向狀語。

【知識鏈接】large amounts of大量；be linked to與……有關(guān)

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？

【參考譯文】你需要等到所有的證據(jù)證明它們有用時才開始服用，還是愿意在現(xiàn)有證據(jù)足以證明它們無害而且可能帶來好處時服用？

【結(jié)構(gòu)分析】這是由or連接的并列句，可以切分為：（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？//）。第一部分的兩個分隔號內(nèi)until…in和before…them均是時間狀語從句，其中的in是形容詞；第二部分的第一個分隔號內(nèi)是that引導的從句，作accept的賓語，第二個分隔號內(nèi)的從句是evidence的同位語。

【知識鏈接】need to do有必要……；sth.is in很流行的，已來到的；be willing to do樂于做……

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

【參考譯文】如果是后者，那就沒有必要走極端，去買最大劑量的藥片或者最貴的藥物。

【結(jié)構(gòu)分析】這是一個主從復合句，If引導的條件狀語從句中出現(xiàn)了省略現(xiàn)象，補全后應(yīng)是：If（it is）the latter；主句中的不定式to go…and buy…bottles是need的后定語。

【知識鏈接】there’s no need to do沒有必要做……；go to extremes走極端；horse pill大片（藥）

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.

【參考譯文】只要你明白任何潛在的益處都是有限的而且需要進一步細化，每天服用多種維生素就有意義了。

【結(jié)構(gòu)分析】這是一個主從復合句，As long as引導條件狀語從句，that引導的是understand的賓語從句，該從句的主語是any potential benefit，謂語是is，表語是modest and subject to，further refinement是介詞to的賓語；主句的主語是動名詞短語taking a daily multivitamin。

【知識鏈接】as long as只要（引導條件狀語從句）；be subject to應(yīng)該……；make a lot of sense很有意義