2005年历年考研英语真题

The human nose is an underrated tool.Humans are often thought to beinsensitive smellers compared with animals,1 this is largely because,2 animals,we stand upright.This means that our noses are 3 to perceiving thosesmells 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 partin one million.Strangely,some people find that they can smell one type of flower but notanother,9 others are sensitive to the smells of both flowers.This may bebecause some people do not have the genes necessary to generate 10 smellreceptors in the nose.These receptors are the cells which sense smells and send11 to the brain.However,it has been found that even people insensitive to a certainsmell 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 it14 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-wesimply do not need to be.We are not 17 of the usual smell of our own house,but we18 new smells when we visit someone else's.The brain finds it best to keep smellreceptors 19 for unfamiliar and emergency signals 20 the smell of smoke,whichmight indicate the danger of fire.1.[A]although[B]as[C]but[D]while2.[A]above[B]unlike[C]excluding[D]besides3.[A]limited[B]committed[C]dedicated[D]confined4.[A]catching[B]ignoring[C]missing[D]tracking英语试题1.(共14页)