单选题 Much ink has been spilled on the question of human hairlessness: why, as Desmond Morris put it in the title of a book published in i967, humankind is "The Naked Ape." Less attention has been paid, though, to the fact that humans are not really hairless at all. Per square centimeter human skin has as many hair follicles (毛囊) as that of other great apes. The difference is in the fineness of the hair. These fine human hairs do not seem to perform any of the functions of their counterparts in more hairy species (insulation and signaling). So what are they for?
That is a question addressed by Isabelle Dean and Michael Siva-Jothy of Sheffield University, in Britain, who took tremendous persuasion and effort to recruit 29 volunteers--19 men and 10 women. Each had a patch of skin on one arm shaved, marked with a pen and surrounded by petroleum jelly, and a patch of the same size on the other marked and surrounded, but not shaved. The bugs had been fed a week and then starved, so they were eager to eat. Volunteers were asked to look away while a researcher put a bug on one of the skin patches. The volunteer was then supposed to record, using a press-button counter, the number of times he perceived the insect moving on his skin.
The difference was significant. When the bug was on a hairy patch it was detected, on average, every four seconds. When it was on a shaved patch, more than ten seconds elapsed between detections. Moreover, the bugs seemed to find it harder to locate a good spot to bite when they were surrounded by hair. Though no volunteer was actually bitten, because the vigilance of the watching researcher meant the insects were removed when they were ready for biting, bugs on hairy skin took about a fifth longer than those on shaved skin to attempt to bite their hosts.
In both cases men were better off than women when the bugs were released on unshaven patches of skin, though there was no significant difference between the sexes when they were shaved. The conclusion is that one reason human body hair has not disappeared completely is to warn and protect us from the attention of hostile insects.

单选题 The author thinks that Desmond Morris and those holding similar views ______.

A. have overlooked the fact
B. have never studied human hairlessness
C. have challenged common sense
D. have raised a good argument

【正确答案】 A

【答案解析】[解析] 第一段前几句说人们花费了许多笔墨探讨人类没有遍体覆毛这个问题：就像Desmond Morris在1967年出版的一本书的书名中所写的那样，为什么人类是“赤裸的猿猴”。不过，人们似乎忽略了这样一个事实，即人类并非真的完全没有体毛。人类皮肤上每平方厘米拥有的毛囊数量和其他大型猿类一样多。区别在于从这些毛囊中长出的毛发的粗细。因此说Desmond Morris没有如实地反映现实。

单选题 Dean and Siva-Jothy hypothesized before the experiment that the body hair of humans ______.

A. is basically useless
B. may eventually disappear
C. performs real functions
D. plays a similar role as that of other species

【正确答案】 C

【答案解析】[解析] 第二段说英国谢菲尔德大学的伊莎贝尔·迪恩和迈克尔·西瓦-乔西就回答了这个问题(即人类体毛的作用)。他们试图通过实验验证这样的想法：纤细的体毛的作用是当床虱这一类可能叮咬人体的爬虫来袭时，向人发出警报。也就是说体毛是有实际功能的。

单选题 1t is implied in the passage that ______.

A. volunteers for the experiment were difficult to find
B. many students were denied the chance to be in the test
C. more volunteers were needed to make the test reliable
D. students in general were interested in the experiment

【正确答案】 A

【答案解析】[解析] 第二段第一句说，迪恩女士和西瓦一乔西博士took tremendous persuasion and effort(费大量口舌)才为他们的研究招募了29名热心的志愿者——包括19男10女。说明招募这样的受试者不是很容易。

单选题 Paragraph 2 focuses on the experiment's ______.

A. requirements
B. procedure
C. feasibility
D. rationale

【正确答案】 B

【答案解析】[解析] 第二段描述了迪恩女士和西瓦-乔西博士的实验是如何实施的，即实验过程。受试者的一只手臂上被剃光一块皮肤，用笔圈上并抹上一圈矿脂(把床虱拦在圈内)，而另一只手臂上也划出同样大小的一块皮肤，同样抹上矿脂，但不剃掉体毛。床虱被禁食一周，因此急于进食。研究人员要求志愿者不要看放在他们手臂上的床虱。实验过程中志愿者要用一个按键式计数器记录他能够察觉到的虫子在皮肤上移动的次数。

单选题 Significant difference was found ______.

A. between male and female volunteers under all conditions
B. when one part of the skin was shaved while the other remained hairy
C. when some bugs were starved while the others were well-fed
D. when some volunteers were allowed to see while the others weren't

【正确答案】 B

【答案解析】[解析] 第三段介绍了实验结果。差别很显著。当床虱被放在有体毛的皮肤表面时，平均每4秒就被察觉到一次。而当它被置于剃光毛发的皮肤上时，超过10秒才会被察觉到一次。说明有无体毛会造成重要的差异。第五段第一句说当床虱被放在有体毛的皮肤上时，男性在上述两方面的表现都好过女性，而当床虱被放在刮去体毛的皮肤上时，两种性别之间没有明显差别。因此答案A不对。

单选题 The findings of the experiment

A. give a reasonable explanation for why human body hair has shrunk
B. fail to establish a link between human body hair and skin problems
C. offer one evidence for why human body hair is still here to this day
D. confirm what we have already known about human body hair

【正确答案】 C

【答案解析】[解析] 最后一段最后一句说，无论出于什么原因人类的体毛变得细小了，它们并未完全消失的一个理由就是它们在害虫来袭时可以起到警报和保护的作用。