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
Scientists in the United States have reported some good news about the ozone in the atmosphere. Recent findings suggest that the
Scientists in the United States have reported some good news about the ozone in the atmosphere. Recent findings suggest that the
admin
2012-09-19
78
问题
Scientists in the United States have reported some good news about the ozone in the atmosphere. Recent findings suggest that the destruction of ozone by pollution is slowing. Ozone is a form of oxygen. Its presence above earth protects us from radiation from the sun.
In one study, researchers examined information gathered by space agency satellites and by equipment on earth. The findings are, in the words of Michael Newchurch of the University of Alabama: "This is the beginning of a recovery of the ozone layer." Mr. Newchurch led the study. He says the atmosphere was losing about 8 percent of the ozone layer per 10-yeas period since the late 1970s. In the last 5 years, though, that rate of loss has dropped by half. He says the atmosphere should start to gain ozone before long. He says a full recovery, however, is about 50 years away, as long as the Montreal Protocol remains in place.
That is an international treaty from 1987 to restore the ozone layer. The treaty restricts the use of a number of chemicals that destroy ozone, like chlorofluorocarbons(氯氟碳化合物), or CFC.
Wide use of CFC began in the 1930s, They became popular coolants in devices such as refrigerators and air conditioners. CFC remains in the atmosphere fox years.
Mr. Newchurch says the study provides evidence that the Montreal Protocol is working by reducing CFC pollution, But the study found the ozone improvement only in the upper stratosphere(平流层). The scientists have not yet seen evidence of similar changes in the lower stratosphere. That holds most of the protective ozone.
The Montreal Protocol also restricts the use of methyl bromide(甲基溴), a chemical to kill insects. Farmers and shippers are the main users. Natural sources of methyl bromide include oceans and some plants. Scientists say the bromine gas it produces is 50 times more destructive to ozone than chlorine(氯气)gas from CFC.
Methyl bromide has never been used as widely as CFC. But a separate study found a decrease in bromine gas levels in the atmosphere. Researchers at the National Oceanic and Atmospheric Administration did the study. They reported a 13 percent drop since 1998. The report is based on 8 years of measurements taken at 10 stations around the world.
American scientists are very concerned about the ozone because ______.
选项
A、the ozone is another form of oxygen
B、the ozone could keep us from the hurt from the sun’s rays
C、the ozone is decreasing as a result of pollution
D、the ozone is very valuable in atmospheric research
答案
B
解析
根据题干American scientists定位到第一段的Scientists in the United States,接着向下浏览,即可发现该段的最后一句话protects us from radiation from the sun说明了臭氧的意义在于能够保护我们免遭太阳辐射,据此可知选B)。A)、C)都是事实,但并没有说明臭氧对人类的益处;D)属于无关选项,原文中未提及其在大气研究中的价值。
转载请注明原文地址:https://kaotiyun.com/show/hi57777K
0
大学英语四级
相关试题推荐
AnewWorldBankreportwarnsthatchildrenwhodonotgetenoughgoodfoodinthefirsttwoyearsoflifesufferlastingdamage
A、Thelivesoftheirparents.B、Makingabetterlifeforallpeople.C、ThetroubleinAmericanfamilies.D、Thestrongopinions.
A、Becausetheyareolderthanyoungpeople.B、Becausetheyoungpeoplewillsoonbeinchargeofthenation.C、Becausethestude
A、Aboutsevenmillion.B、NearlyhalfoftheAmericanpopulation.C、25%ofAmericanpeople.D、Wedon’tknowexactlyfromthepass
Manypeoplewronglybelievethatwhenpeoplereacholdage,theirfamiliesplacetheminnursinghomes.Theyareleftinthehan
A、Recordcompaniesshouldpayattentionnottooffendpeople.B、Recordcompaniesshouldbeverycarefulwiththeiremployees.C、
InatimeoflowacademicachievementbychildrenintheUnitedStates,manyAmericansareturningtoJapan,acountryofhigha
随机试题
A.意识不清,突然转佳B.心烦不宁,呼号骂闹C.表情淡漠,哭笑无常D.意识模糊,目光呆滞E.昏不知人,四肢抽动患者,女,31岁。患癫痫病多年,发作时突然出现神志异常,临床表现可见
在单缝夫琅禾费衍射实验中,波长为λ的单色光垂直入射到单缝上,对应衍射角为30°的方向上,若单缝处波面可分成3个半波带,则缝宽度α等于()。[2012年真题]
风管组对时,风管连接处采用密封材料应满足()的技术条件。
无形磨损的局部补偿形式是()。
马柯威茨理论的最大问题是计算量太大,特别是对大规模的市场存在上千种证券的情况下,哪怕是借助高速计算机也难以实现。( )
孔子曰:“信则人任焉”,这句话与下列《银行业从业人员职业操守》中()原则的要求相似。
以每股利润最大化作为财务管理的目标考虑了资金的时间价值但没有考虑投资的风险价值。()
2012年,安徽省铜陵市规模以上工业企业完成总产值1622.4亿元,增长7.4%;实现工业增加值408.7亿元,增长11.2%。工业经济发展对全市经济增长的贡献率达69.7%,拉动GDP增长7.7个百分点。全年战略性新兴产业完成工业总产值382.1亿元,增
在文言文中“社稷”一般指代________,其中“社”指________、“稷”指________。
公司将一张面额为10000元,3个月后到期的商业票据变现,若银行年贴现率为5%,应付金额为()元。[上海财经大学2013研]
最新回复
(
0
)