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
It didn’t happen overnight. The problem of polluted air has been festering for centuries. Suddenly the problem of air pollut
It didn’t happen overnight. The problem of polluted air has been festering for centuries. Suddenly the problem of air pollut
admin
2015-01-09
26
问题
It didn’t happen overnight. The problem of polluted air has been festering for centuries.
Suddenly the problem of air pollution is becoming critical and is erupting right before our eyes. Not only do our eyes burn as they focus through murky air,but when the air clears,we see trees and vegetation dying. We must realize that this destruction can no longer be pinned to some mysterious cause. The one major culprit is air pollution.
Today’s air pollution is an unfortunate by-product of the growth of civilization. Civilized mall desires goods that require heavy industrialization and mass production. Machines and factories sometimes pollute and taint the air with substances that are dangerous to man and the environment. These substances include radioactive dust,salt spray,herbicide and pesticide aerosols, liquid droplets of acidic matter,gases, and sometimes soil particles. These materials can act alone to irritate objects and forms of life. More dangerously,they join together to act upon the environment. Only lately have we begun recognizing some of their dangerous consequences.
Scientists have not yet been able to obtain a complete report on the effects of air pollution on trees. They do know,however,that sulfur dioxide,fluorides,and ozone destroy trees and that individual trees respond differently to the numerous particulate and gaseous pollutants. Sometimes trees growing in a single area under attack by pollutants will show symptoms of injury or will die while their neighbors remain healthy. Scientists believe this difference in response depends on the kind of tree and its genetic makeup. Other factors,such as the tree’s stage of growth and nearness to the pollution source,the amount of pollutant,and the length of the pollution attack also play a part. In short,whether or not a tree dies as a result of air pollution depends on a combination of host and envimnmental factors.
For the most part,air pollutants injure trees. To conifers,which have year-round needles,air pollution causes early balding. In this event,trees cannot maintain normal food production levels. Undernourished and weakened, they are open to attack by a host of insects,diseases,and other environmental stresses. Death often follows.
Air pollution may also cause hardwoods to lose their leaves. Because their leaves are borne only for a partion of the year and are replaced the following year.air pollution injury to hardwoods may not be so severe.
The author implies that the greatest source of pollution is____.
选项
A、heavy industry
B、chemical processing plants
C、urban expansion
D、salt spray
答案
A
解析
题目问:作者暗示,最大的污染源是什么?第三段第二句“Civilized mall desires goods that requireheavy industrialization and mass production”,通过这句话可知,生产商品需要重工业的支持,伴随而来的就是环境污染。据此判断,应选择据此A.
转载请注明原文地址:https://kaotiyun.com/show/hdQO777K
0
考博英语
相关试题推荐
Atmanycolleges,smokersarebeingrunnotjustoutofschoolbuildingsbutoffthepremises.OnNov.19,theUniversityofKen
TheUnitedNationsPopulationFundhaspickedOctober31asthedaytheworldwillbehometo7billionpeople.Forbettera
ThefieldofsociologyintheUnitedStatesdevelopedasaresultofasocialexperiencewhichhadverylittletodowiththepo
CharlesDarwin’s"OntheOriginofSpecies"iscreditedwithsparkingevolution’srevolutioninscientificthought,butmanyobs
IfyouhappenedtobewatchingNBConthefirstSundaymorninginAugustlastsummer,youwouldhaveseensomethingcurious.The
Sociologistsusethetermpowertorefertothecapacityofpeopleorgroupstocontrolorinfluencetheactionsofothers,whet
AnOhioStateUniversitystudyhaslinkedbehaviorinyoungchildren【1】thetypeofjobtheirmotherhas.Motherswithcomplexoc
Alisonclosedthedoorofhersmallflatandputdownherbriefcase.Asusual,shehadbroughtsomeworkhomefromthetravelag
Whentravelerslackanawarenessof【51】timeisregulatedinaforeigncountry,theycanexpecttofeelsomewhatdisoriented.S
Shewasextremelylucky;whenhergreat-uncledied,she______afortune.
随机试题
企业采用分期收款销售的方式,在不符合收入确认条件但商品已经发出的情况下,对分期收款销售的商品,应设置的科目是
A.因人制宜B.治未病C.因时制宜D.寒因寒用E.因地制宜“先安未受邪之地”属于
肺胀发病的主要病理因素是
根据《安全生产事故隐患排查治理暂行规定》,下列说法中,错误的是()。
如图所示结构1、2杆轴力为( )。
下列选项不属于学校及其他教育机构应当履行的义务的是()。
(2013下集管)某公司的质量目标是每千行代码缺陷数不大于2.5个,项目组为确保并能对软件开发项目组5个代码编写人员各自的质量进行趋势分析,适合质量工具是______。
母は魚の肉を____、猫に食べさせた。
Iwasnervous—desperatelynervous—aboutbecomingcar-free.Buteightmonthsagoourcarwashit,andthedamagewassobaditha
A、Tofindoutexactlywhathappens.B、Tosavefueltoflylonger.C、Tofindoutwherethebigstoneis.D、Toflyevenmoreslowl
最新回复
(
0
)