Though sucking zinc lozenges has been promoted as a treatment for the common cold, research has revealed no consistent effect. Recently, however, a zinc gel applied nasally has been shown to greatly reduce the duration of colds. Since the gel contains zinc in the same form and concentration as the lozenges, the greater effectiveness of the gel must be due to the fact that cold viruses tend to concentrate in the nose, not the mouth.
Which of the following, if true, most seriously weakens the argument?
A. Experimental subjects who used the zinc gel not only had colds of shorter duration but also had less severe symptoms than did those who used a gel that did not contain zinc.
B. The mechanism by which zinc affects the viruses that cause the common cold has not been conclusively established.
C. To make them palatable, zinc lozenges generally contain other ingredients, such as citric acid, that can interfere with the chemical activity of zinc. 因为后者zinc的存在形式和前者的是一样，如果前者掺杂了其他的东西，同样后者也存在这些成分，这些成分can interfere with the chemical activity of zinc，所以他的功效可能不是文中所提及的。weaken。愚见
D. No zinc-based cold remedy can have any effect unless it is taken or applied within 48 hours of the initial onset of cold symptoms.
E. Drug-company researchers experimenting with a nasal spray based on zinc have found that it has much the same effect on colds as the gel does.
这题我明白题意，但是不明白为什么选C？C选项如何削弱文章呢？不明白，麻烦各位帮帮忙，谢谢
In many scientific disciplines, scientists generally do not do highly creative work beyond the age of forty, a tendency that has normally been taken to show that aging carries with it a loss of creative capacity.However, by the age of forty most scientists have been working in their chosen field for at least fifteen years, so an alternative explanation is that spending too long in a single field reduces the opportunity for creative thought.
Investigating which of the following would be most useful in choosing between the competing explanations described above?
A. Whether among those scientists who do highly creative work beyond age forty a large proportion entered their field at a considerably later age than is common
如果按照作者的说法，一般的学术周期不超过15年，长了就倦怠了，那么对于过了40岁还在工作的人，他们是例外呢还是也是印证了作者的判断呢（即晚入行晚退休） 愚见
B. Whether scientists' choice of research projects tends to be influenced by their own belief that their most creative work will be done relatively early in their career
C. Whether scientists who are older than forty tend to find more satisfaction in other activities, such as teaching and mentoring, than they do in pursuing their own research
D. Whether funding agencies are more inclined to award research grants to scientists who are veterans in their field than to scientists who are relative newcomers
E. Whether there is significant variation among scientific fields in the average age at which scientists working in those fields are at their most productive
还有这题选A是为什么呢
-- by 会员 ken178 (2010/8/28 23:26:44)
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发表于 2010-8-28 23:26:44
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