绝密★启用前
2005 年全国硕士研究生招生考试
英语
（科目代码：201）
☆考生注意事项☆
答题前，考生须在试题册指定位置上填写考生编号和考生姓名；在答题卡指定位置上填写报考单位、考生姓名和考生编号,并涂写考生编号信息点。
考生须把试题册上的“试卷条形码”粘贴条取下，粘贴在答题卡的“试卷条形码粘贴位置”框中。不按规定粘贴条形码而影响评卷结果的，责任由考生自负。
选择题的答案必须涂写在答题卡相应题号的选项上，非选择题的答案必须书写在答题卡指定位置的边框区域内。超出答题区域书写的答案无效；在草稿纸、试题册上答题无效。
填（书）写部分必须使用黑色字迹签字笔书写，字迹工整、笔迹清楚；涂写部分必须使用 2B 铅笔填涂。
考试结束，将答题卡和试题册按规定交回。
（以下信息考生必须认真填写）
考生编号
考生姓名

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 nec