首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
About ten men in every hundred suffer from color blindness in some way; women are luckier only about one in two hundred is affec
About ten men in every hundred suffer from color blindness in some way; women are luckier only about one in two hundred is affec
admin
2010-09-25
51
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.
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://jikaoti.com/ti/DHeFFFFM
0
大学英语六级
相关试题推荐
Intheinterestoflightnessofweight,everythingyoucarryinyourpackshouldserveasmanypurposesaspossible.Clothingan
TheEnvironmentalProtectionAgencyhassetlimitsfortheradiationpermittedtoleakfromaproposednuclearwasteburialcent
A、Moreandmorepeoplearesufferingfromheartdisease.B、Moreandmoredoctorsarefocusingtoomuchondietandexercise.C、P
LetChina’sRetailWarsBeginNewlyunfetteredforeignchainscouldgrabmoreofChina’smarket.OnacoldandwindyFriday
FactsaboutDepressionInanygivenone-yearperiod,9.5%ofthepopulation,orabout18.8millionAmericanadults,sufferf
A、10points.B、2points.C、15points.D、5points.D与题干中的misspellsaword相关的原文信息是Amisspelledwordwillcostyou5points,由此可知,拼写
__________________(我们应该开发本地区自然资源的建议)hasbeendiscussedattheconference.
OnesummermywifeandIwereinvitedbyfriendstorowdowntheColoradoRiverinaboat.Ourexpeditionincludedmanyhighlys
A、Inthemorning.B、Intheearlyafternoon.C、Intheevening.D、Atmidnight.A
Whyaresomanypeopleunhappyintheirjobs?Therearetwoprimaryreasons.First,somepeopleareconvincedthatearningaliv
随机试题
在制作使用路径控制动画补间时,下列工具能绘制出所需路径的是。
Thenumberofpeopleborrowingfrompubliclibrarieshasdecreased,(butbooksalesarerising).
p受体阻滞药可用于哪种心律失常的治疗
灭菌制剂的灭菌目的不包括
2013年4月17日,某县地税局工作人员张某等三人,在对陈某的烟酒店进行检查时发现,陈某有伪造完税凭证的行为,对陈某作出罚款500元的行政处罚。同时张某向陈某表示,如果陈某赠送一条好烟,可以免除处罚。两人因此发生口角,进而动手,造成陈某轻微伤。陈某花费医疗
2005年4月1日,甲公司销售一批商品给乙公司,开出的增值税专用发票上注明销售价款为50万元,增值税销项税额为8.5万元,乙公司签发并承兑了一张商业汇票,票面值为58.5万元,票面利率为6%,期限为6个月。2005年6月1日,甲公司因急需流动资金,经与中国
学生的学习,一般地说主要是系统地学习()的过程。
我国著名药学家屠呦呦获得诺贝尔医学奖,这是源于她在创制新型抗疟疾药()的突出贡献。
函数smove(intA[],intn)的功能是将数组中所有的奇数都放到所有偶数之前,其过程为:设置数组元素下标索引i(初值为0)和j(初值为n-1),从数组的两端开始检查元素的奇偶性。若A[i]、A[j]都是奇数,则从前往后找出一个偶数,再与A[j]
三次独立试验中A发生的概率不变,若A至少发生一次的概率为19/27,则一次试验中A发生的概率为________.
最新回复
(
0
)