全国硕士研究生入学统一考试---英语2005年试题及解析
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2005年全国硕士研究生入学考试英语试题及答案
section i use of english
directions:
read the following text. choose the best word(s) for each numbered blank and mark a, b, c or d on answer sheet 1. (10 points)
the human nose is an underrated tool. humans are often thought to be insensitive smellers compared with animals, (1) ____ this is largely BECause, (2) ____ animals, we stand upright. this means that our noses are (3) ____ to perceiving those smells which float through the air, (4) ____ the majority of smells which stick to surfaces. in fact, (5) ____, we are extremely sensitive to smells, (6) ____ we do not generally realize it. our noses are capable of (7) ____ human smells even when these are (8) ____ to far below one part in one million.
strangely, some people find that they can smell one type of flower but not another, (9) ____ others are sensitive to the smells of both flowers. this may be because some people do not have the genes necessary to generate (10) ____ smell receptors in the nose. these receptors are the cells which sense smells and send (11) ____ to the brain. however, it has been found that even people insensitive to a certain smell (12) ____ can suddenly become sensitive to it when (13) ____ to it often enough.
the explanation for insensitivity to smell seems to be that the brain finds it (14) ____ to keep all smell receptors working all the time but can (15) ____ new receptors if necessary. this may (16) ____ explain why we are not usually sensitive to our own smells —— we simply do not need to be. we are not (17) ____ of the usual smell of our own house, but we (18) ____ new smells when we visit someone else’s. the brain finds it best to keep smell receptors (19) ____ for unfamiliar and emergency signals (20) ____ the smell of smoke, which might indicate the danger of fire.
