首页
登录
职称英语
About ten men in every hundred suffer from color blindness in some way; wom
About ten men in every hundred suffer from color blindness in some way; wom
游客
2023-09-09
7
管理
问题
About ten men in every hundred suffer from color blindness in some way; women are luckier only about one in two hundred is affected in this manner. There are different forms of color blindness. A man may not be able to see deep red. He may think that red, orange and yellow are all shades of green. Sometimes a person cannot tell the difference between blue and green. In rare cases an unlucky man may see everything in shades of green--a strange world indeed.
In certain occupations color blindness can be dangerous and candidates are tested most carefully. For example, when fighting at night, soldiers use lights of flares to signal to each other. A green light may mean "Advance" and a red light may mean "Danger! Keep back!" You can see what will happen if somebody thinks that red is green! Color blindness in human beings is a strange thing to explain. In a single eye there are millions of very small things called "cones". These help to see in a bright light and to tell the difference between colors. There are also millions of "rods" but these are used for seeing when it is nearly dark. They show us shape but not color. Wait until it is dark tonight, and then go outside. Look round you and try to see what colors you can recognize.
Birds and animals which hunt at night have eyes which contain few or no cones at all, so they cannot see colors. As far as we know, bats and adult owls cannot sec colors at all only light and dark shapes. Similarly cats and dogs cannot see colors as well as we can.
Insects can see ultra-violet rays which are invisible to us, and some of them can even see X-rays. The wings of a moth may seem gray and dull to us, but to insects they may appear beautiful, showing colors which we cannot see. Scientists know that there are other colors around us which insects can see but which we cannot see. Some insects have favorite colors. Mosquitoes like blue, but do not like yellow. A red light will not attract insects but a blue lamp will. [br] When millions of rods in our eyes are at work in darkness, we can see ______.
选项
答案
shapes only
解析
由题干关键词millions of rods定位原文第二段,由该段倒数第二句话中的They show us shape but not color可知,答案是shapes only。
转载请注明原文地址:https://tihaiku.com/zcyy/3000121.html
相关试题推荐
Throughouttheworld36millionpeoplearesufferingfromAIDS,whichismoreth
[originaltext]Aboutahundredyearsago,thepeopleofLondonwereamazedt
[originaltext]Aboutahundredyearsago,thepeopleofLondonwereamazedt
[originaltext]Manypeoplesufferfromsomeformofextremeanxiety.Someex
[originaltext]Manypeoplesufferfromsomeformofextremeanxiety.Someex
HealthCareandEpidemicsEveryonesuffersfromdiseasea
HealthCareandEpidemicsEveryonesuffersfromdiseasea
HealthCareandEpidemicsEveryonesuffersfromdiseasea
HealthCareandEpidemicsEveryonesuffersfromdiseasea
HealthCareandEpidemicsEveryonesuffersfromdiseasea
随机试题
[originaltext]W:Hello,John.Youmustbepleased.Afterallhowmanystudents
NarratorListentopartofalectureinageographyclass.Nowget
Beforethe1850’s,theUnitedStateshadanumberofsmallcolleges,mostofthe
处理期刊页面余缺常用的方法有( )等。A.抽稿 B.增稿 C.调换栏目
依据《支付结算办法》的规定,下列关于支付结算的说法中,正确的是()。A.未使用按
下列各项基金中,属于事业单位事业基金的有()。A.一般基金 B.非流动资
以下属于“日常危害健康行为”的是A:药物滥用 B:讳疾忌医 C:不遵医嘱
男性,71岁,吸烟患者。反复咳嗽、咳痰、气促40余年,胸闷、心悸2年,加重伴发
A.国务院食品药品监督管理部门注册 B.国务院食品药品监督管理部门备案 C.
已知某企业销售收款政策为:当月收现50%,下月收现30%,再下月收现20%。若该
最新回复
(
0
)