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
A pure virus(病毒)could be kept in a bottle, just like hundreds of other chemicals. Yet, when a virus is placed on a living thing,
A pure virus(病毒)could be kept in a bottle, just like hundreds of other chemicals. Yet, when a virus is placed on a living thing,
admin
2016-11-16
138
问题
A pure virus(病毒)could be kept in a bottle, just like hundreds of other chemicals. Yet, when a virus is placed on a living thing, it comes to life. As long as it is on a living material, it grows.
A difficult question still remains—what is a virus? Is it living or chemical? Men of science had always thought life and not-life to be as different as black and white. With the discovery of the virus , they became aware of
a grey area
that was neither black nor white.
Until the 1930’ s, it was accepted that there was also a great difference in size between the largest chemical molecules(分子)and the smallest living things. As new and much finer filters(过滤器)were invented, men were able to measure viruses. The first virus to be measured was found to be about 100 millimicrons(毫微米)across.
The largest known chemical molecule measures only 22 millimicrons. The smallest living thing measures almost seven times that size or 150 millimicrons. When viruses were measured, they were found to range in size from 16 millimicrons to 300 millimicrons. Most were found to be larger than the largest chemical molecules and smaller than the smallest living things.
The answer to the puzzle—what is a virus? —must be that it is both living and not living. In a living cell, it is a live thing. In a bottle, it is nothing more than a chemical. We now realize that the virus is actually a link between life and not-life.
Which of the following is the smallest in size?
选项
A、Viruses.
B、New filters.
C、Living cells.
D、Chemical molecules.
答案
D
解析
推理题。题干意为“以下几个选项中,哪个是尺寸最小的?”。根据文章倒数第二段最后一句“…larger than the largestchemical molecules and smaller than the smallest living things.”可知,通过三者的比较,应该是chemical molecules最小。故D为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/K7ud777K
本试题收录于:
公共英语二级笔试题库公共英语(PETS)分类
0
公共英语二级笔试
公共英语(PETS)
相关试题推荐
Onesummerdaymyfathersentmetobuywireforourfarm.At16,Iliked【C1】______betterthandrivingourtrack,【C2】______this
RadioStar,______bytheEnglishDepartment,isverypopularwiththestudents.
Whereprobablyarethespeakers?
Wherearethespeakers?
假定你是李明,你的英国朋友Dave与你在同一个城市土作。你去邀请他和你一起参观一个中国画展。他不在,请你根据以下要点给他写个留言条。要点:1.介绍画展•中国画•历代名画展•展期:本月8日—18日•地点:艺术博
HowmanybrothersandsistersdoesPanchohave?
Thestreetisbeautiful,fortherearetreeson______.
MartinLutherKingJr.wasborninGeorgiain1929.Whenwas【36】aboyMartinlearnedthathis【37】,theblackAmericans,were【38】
Mr.Duffhadseveralfarmsinthevillage.He36someworkersandmadethemworkmorethantwelvehoursa37Hedidn’tsupplyth
Ihope______roundthetouristsitesbyaspecialistguide.
随机试题
我国中学二级和三级教师职务由()
雨期填筑路堤需借土时,取土坑距离填方坡脚不宜小于()。
会计核算软件在进行系统初始化时,必须输入操作人员岗位分工情况,但为了保密,可以不输入操作密码。()
根据刑事法律制度的规定,下列有关对共同犯罪人的处罚,表述不正确的有()。
下列有关税法特点的说法,错误的是()。(2011年真题)
可以通过管理决策行动改变的成本包括()。
票据权利应在法定期限内行使,下列选项中将造成票据权利消灭的有()。
除一人有限责任公司外,有限责任公司全体股东的首次出资额不得低于注册资本的20%,也不得低于法定的注册资本最低限额,其余部分由股东自公司成立之日起两年内缴足;其中,投资公司可以在5年内缴足。()
加拿大的国树是(),也是加拿大民族的象征。
a,b取何值时,方程组有解?
最新回复
(
0
)