英语一/2005/第一部分/人类的嗅觉

PS：尝试以BOM方式进行记录，参考书籍为世纪高教黄皮书；

日期说明：研读&记录的日期；

编号说明：[年份].[文章顺序].[段落顺序].[句子顺序]，如：[04.02.03.05]——04年试卷、第2篇文章、第3段、第5句；

2023/04/12

05.01.01.01

The human nose is an underrated tool.

05.01.01.02

Humans are often thought to be insensitive smellers compared with animals, but this is largely because, unlike animals, we stand upright.

05.01.01.03

This means that our noses are limited to perceiving those smells which float through the air, missing the majority of smells which stick  to surfaces.

05.01.01.04

In fact, thought, we are extremely sensitive to smells, even if we don not generally realize it.

05.01.01.05

Our noses are capable of detecting human smells even when these are diluted to far below one part in one million.

05.01.02.01

Strangely, some people find that they can smell one type of flower but not another, whereas others are sensitive to the smells of both flowers.

05.01.02.02

This may be because some people do not have the genes necessary to generate particular smell receptors in the nose.

05.01.02.03

These receptors are the cells which sense smells and send messages to the brain.

05.01.02.04

However, it has been found that even people insensitive to a certain smell at first can suddenly become sensitive to it when exposed to it often enough.

05.01.03.01

The explanation for insensitivity to smell seems to be that the brain finds it inefficient to keep all smell receptors working all the time but an create new receptors if necessary.

05.01.03.02

This may also explain why we are not usually sensitive to our own smells--we simply do not need to be.

05.01.03.03

We are not aware of the usual smell of our own house, but we notice new smells when we visit someone else's.

05.01.03.04

The brain find it best to keep smell receptors available for unfamiliar and emergency signals such as the smell of smoke, which might indicate the danger of fire.

（这篇比前面的简单好多）

（这篇开始花点时间把生词加粗，虽然在电脑的excel上已经做过了，传一遍专栏就当复习吧）