真是笨，这题又不会了，给位大侠帮帮忙！

astronautking

Thoughsucking 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 greatlyreduce the duration of colds.  Since thegel contains zinc in the same form and concentration as the lozenges, thegreater effectiveness of the gel must be due to the fact that cold viruses tendto concentrate in the nose, not the mouth.
Whichof the following, if true, most seriously weakens the argument?
A.Experimental subjects who used the zinc gel not only had colds of shorterduration but also had less severe symptoms than did those who used a gel thatdid not contain zinc.
B.The mechanism by which zinc affects the viruses that cause the common cold hasnot been conclusively established.
C. To make them palatable, zinc lozenges generally contain otheringredients, such as citric acid, that can interfere with the chemical activityof zinc.
D.No zinc-based cold remedy can have any effect unless it is taken or appliedwithin 48 hours of the initial onset of cold symptoms.
E.Drug-company researchers experimenting with a nasal spray based on zinc havefound that it has much the same effect on colds as the gel does.

clumsy123

答案是选C么

astronautking

答案是选C么

-- by 会员 clumsy123 (2011/4/22 21:17:42)

这么厉害啊！是啊！劳烦讲解一下呗！

clumsy123

The argument said that although the zinc lozenges can be used to treat cold, it doesn't always have the same effect(that is, it doesn't always success to treat the cold). However, the zinc gel which is applied nasally(in the mouth) can treat the cold more successfully.

So the argument concluded that  the zinc gel has greater effectiveness than the zinc lozenges because the cold viruses concentrate in the nose, not in the mouth.

so C can weaken the argument because it raises another reason that may explain the different effectiveness between the gel and lozenges. IF lozenges contains certain ingredients which would weaken its effectiveness, it can not be true that different concentrations  of viruses lead to different effectiveness.

哎呀，第一次用英文解释。。。说的不好莫见怪。。如果没懂，我再用中文说一遍吧~

astronautking

The argument said that although the zinc lozenges can be used to treat cold, it doesn't always have the same effect(that is, it doesn't always success to treat the cold). However, the zinc gel which is applied nasally(in the mouth) can treat the cold more successfully.

So the argument concluded that  the zinc gel has greater effectiveness than the zinc lozenges because the cold viruses concentrate in the nose, not in the mouth.

so C can weaken the argument because it raises another reason that may explain the different effectiveness between the gel and lozenges. IF lozenges contains certain ingredients which would weaken its effectiveness, it can not be true that different concentrations  of viruses lead to different effectiveness.

哎呀，第一次用英文解释。。。说的不好莫见怪。。如果没懂，我再用中文说一遍吧~

-- by 会员 clumsy123 (2011/4/23 9:00:22)

Got it,thanks a lot!( Your English explanation is clear!)