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
55
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 attributes today’s air pollution to____.
选项
A、the growth of civilization
B、man’ s carelessness
C、environmental imbalance
D、some mysterious cause
答案
A
解析
题目问:作者把今天的空气污染归因于什么?第三段“Today’s air pollution is an unfortunate by—product of the growth of civilization”,通过这句话可知,当今的空气污染是人类文明发展过程中的一个不良副产品。据此判断,应选择A。
转载请注明原文地址:https://kaotiyun.com/show/GdQO777K
0
考博英语
相关试题推荐
Atmanycolleges,smokersarebeingrunnotjustoutofschoolbuildingsbutoffthepremises.OnNov.19,theUniversityofKen
(1)AgiftedAmericanpsychologisthassaid,"Worryisaspasmoftheemotion;themindcatchesholdofsomethingandwillnotle
Thebombingcampaignis______yearsofcivilconflictanddroughttocreateanenvironmentalcrisis.
Weareapeacefulcommunitybutwecannot______andallowthepeopleresponsibletodestroythefabricofoursociety.
ThefieldofsociologyintheUnitedStatesdevelopedasaresultofasocialexperiencewhichhadverylittletodowiththepo
Moststudiesfocusonremarkablyprecisesliversofhumanemotions.OnestudyatAlleghenyUniversityinPennsylvaniafoundthat
Therelationshipbetweentechnologyanddevelopmentiscomplicated.Attimesthenegativefeaturesoftechnologyseemto______th
Therearethreeseparatesourcesofhazard【1】totheuseofnuclearreactiontosupplyuswithenergy.Firstly,theradioactivem
IsecondMr.Smith’smotionthatwe______aspecialboardtoexaminetheproblem.
Thelong-termfortunesofthemodemeconomydependinpartonthestrengthandsustainabilityofthefamily,bothinrelationto
随机试题
恶性成釉细胞瘤不包括
下列劳动合同或劳务合同,哪些属于劳动法的调整范围?
屋面竖向均布荷载设计值为1.2kN/m2(包括屋面结构自重、雪荷载、灰荷载;按水平投影计算)。单跨简支的檩条(A3)在竖向荷载作用下的最大弯矩设计值(kN.m),与下列何项数值最为接近?
下列关于仲裁裁决执行的说法中错误的是( )。
银行存款余额调节表、银行对账单是会计档案,但不是原始凭证。()
根据《票据法》的规定,支票的记载事项可以授权补记的有()。
将关键事件归并为若干绩效指标,并建立绩效评价等级的绩效考评方法为()。(2004年11月二级真题)
教育机智是教师在教育、教学过程中的一种特殊定向能力,是教师对学生活动的敏感性,能根据学生新的特别是意外的情况,迅速而正确地作出判断,随机应变地及时采取恰当而有效的教育措施解决问题的能力。根据上述定义,下列哪项体现出了教育机智?()
法律权威源自()
引用列表框(Listl)最后一个数据项应使用的表达式是()。
最新回复
(
0
)