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
32
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 re-spond 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 pol-lutant,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 envimn-mental 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/6hLO777K
0
考博英语
相关试题推荐
Bigcitiestodayareconfrontedwithveryseriousproblems.Transportisa【1】difficulty:someplannersbelievein【2】transportsy
Bigcitiestodayareconfrontedwithveryseriousproblems.Transportisa【1】difficulty:someplannersbelievein【2】transportsy
Bigcitiestodayareconfrontedwithveryseriousproblems.Transportisa【1】difficulty:someplannersbelievein【2】transportsy
Bigcitiestodayareconfrontedwithveryseriousproblems.Transportisa【1】difficulty:someplannersbelievein【2】transportsy
Shefeltdizzyandhadto______somethingtosteadyherself.
Themostexcitingkindofeducationisalsothemostpersonal.Nothingcan【1】thejoyofdiscoveringforyourselfsomethingthat
Themostexcitingkindofeducationisalsothemostpersonal.Nothingcan【1】thejoyofdiscoveringforyourselfsomethingthat
Themostexcitingkindofeducationisalsothemostpersonal.Nothingcan【1】thejoyofdiscoveringforyourselfsomethingthat
Recentlyscientistshavebeen【1】andperfectingothersourcesofenergy:nuclearoratomicpower,solar(sun)power,andsynthetic(
Recentlyscientistshavebeen【1】andperfectingothersourcesofenergy:nuclearoratomicpower,solar(sun)power,andsynthetic(
随机试题
患者,男性,31岁。持续性头痛6天。自觉后枕部紧箍样疼痛,无恶心、畏光和畏声。查体:T36.5℃,BP120/70mmHg,眼压无异常,张口颞颌关节无异常。脑部MRI无异常。最可能的诊断是
退行性骨关节病关节面下透光区引起的原因是
甲国某航空公司国际航班在乙国领空被乙国某公民劫持,后乙国将该公民控制,并拒绝了甲国的引渡请求。两国均为1971年《关于制止危害民用航空安全的非法行为的公约》等三个国际民航安全公约缔约国。对此,下列哪一说法是正确的?(2013年卷一第33题)
调整工程网络计划时,调整内容一般包括()。
下列关于股票期权投资策略的说法中,不正确的是()。
企业摊销无形资产时,可能借记的会计科目有()。
有关密码管理,下列说法错误的是()。
阅读下面程序:#include<iostream.h>fun(inta,intb){intc;c=a+b:returnC;)voidmain(){intx=6,y=7,z=8,r;r=fun((x--,y++,x+y),z-
HappyLand,abigfamilyrestaurant______theregionfortenyears,iscurrentlyofferinga20percentdiscount.
Ilovetravelingbytrain.Fast【B1】______slowlocaltrainswhichstopsateverystation,【B2】______trainstakingbusinessmen
最新回复
(
0
)