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
52
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
Scientistsuseobservationandexperimentationtoexamineaspecificconcept______existingtheoriesandprinciples.
PeopleplanningtotravelbycartoNorthDakotainthewinterareadvisedto______theircarswithsnowtiresandwarmclothing
Manyadultsmaythinktheyaregettingenoughshut-eye,butinamajorsleepstudyalmost80percentofrespondentsadmittedto
Sociologistsusethetermpowertorefertothecapacityofpeopleorgroupstocontrolorinfluencetheactionsofothers,whet
Sociologistsusethetermpowertorefertothecapacityofpeopleorgroupstocontrolorinfluencetheactionsofothers,whet
Alittlemorethanacenturyago,MichaelFaraday,anotedBritishphysicist,managedtogainaudiencewithagroupofhighgove
Theinkhadfadedwithtimeandsopartsoftheletterwereillegible.
Thepolicehaveaskedforthe____ofthepublicintracingthewhereaboutsofthemissingchild.
Marywasextremelylucky:whenhergreat-uncledied,she_____afortune.
Alisonclosedthedoorofhersmallflatandputdownherbriefcase.Asusual,shehadbroughtsomeworkhomefromthetravelag
随机试题
不同种类的生物分解嘌呤的能力不同。()
关于高分子的溶解与溶胀的叙述中错误的是()
肝火犯胃型吐血的主症不包括
A.食积便秘B.血虚便秘C.气虚便秘D.脾约便秘E.冷积便秘麻子仁丸主治的是()
气虚感冒的治法是阴虚感冒的治法是
女孩,10岁。全身水肿2周。尿蛋量4.5g/24h,血浆白蛋白20g/L,血脂升高行肾脏穿刺活检,光镜下肾小球未见异常。电镜下肾小球最可能的病理变化是
定性风险分析的依据包括()。
运输作业中所涉及的组织称作“当事人”,其中“当事人”包括托运人、承运人、代理人(包括无船承运人和国际多式联运经营人)和收货人。()
2017年1月1日,某股份有限公司未分配利润为100万元,2017年度实现净利润400万元,法定盈余公积的提取比例为10%,不考虑其他因素,下列关于盈余公积的账务处理正确的是()。
实施股票分割与发放股票股利产生的效果相似,它们都会()。
最新回复
(
0
)