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
Narrator Listen to part of a talk in an environmental science class. Now get ready to answer the questions. You may use your not
Narrator Listen to part of a talk in an environmental science class. Now get ready to answer the questions. You may use your not
admin
2013-08-12
60
问题
Narrator
Listen to part of a talk in an environmental science class.
Now get ready to answer the questions. You may use your notes to help you answer.
What is the talk mainly about?
Narrator
Listen to part of a talk in an environmental science class. Professor
How much can you say about air pollutant? At first let’s have a look at a useful definition of it. A pollutant is a compound added directly or indirectly by humans to the atmosphere, and in such quantities to adversely affect humans, animals, vegetations or materials. On the other hand air pollution has a very flexible definition that allows continuous change. When the first air pollution law was established in England in the 14th century, air pollutants were limited to compounds that could be seen or smelled, which is very different from the list of harmful substances known today. As technology has developed and knowledge of health aspects has increased, the list of air pollutants has lengthened. In the future even water vapor might be thought of as an air pollutant under certain conditions
Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides are found in nature. Perhaps in your daily life you can’t feel them clearly since they don’t make up a big percentage of the air. Before we have learnt something about the properties of the above substances, let’s have a look at their historical development. As the earth developed, the concentrations of these pollutants were altered by various chemical reactions and become biogeochemical components, and then they serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature’s output of these compounds dwarfs those resulting from human activities. However, human production usually occurs in a localized area, such as a city.
In these localized regions, human output may be dominant and may temporarily overload the natural purification scheme of cycles. The result is an increased concentration of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the concentration tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million, often shortened to ppm, which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.
Now get ready to answer the questions. You may use your notes to help you answer.
24. What is the talk mainly about?
25. According to the speaker, what is the feature of air pollutants?
26. According to the speaker, what might be an air pollutant in the future?
27. What may be influenced by air pollutants?
Listen again to part of the lecture. Then answer the question.
Professor
The actual concentration need not be large for a substance to be a pollutant; in fact the concentration tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.
28. What does the professor mean when he says this?
Professor
In fact the concentration tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.
29. What can be inferred from this?
Professor
As the earth developed, the concentrations of these pollutants were altered by various chemical reactions and become biogeochemical components, then they serve as air purification scheme by allowing the compounds to move from the air to the water or soil.
选项
A、The definition of air pollutant.
B、The causes of air pollution.
C、The dangers of air pollutants.
D、Ways to fight air pollution.
答案
A
解析
本题为要点题,要求考生必须具备综合概括文章主要信息的能力。题目问的是全文的中心思想,综合原文不难看出话题是围绕空气污染物的定义而展开的,而不是它的原因、危害性和预防方法,由此可见A项应为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/i1fO777K
0
托福(TOEFL)
相关试题推荐
CompletethenotesbelowusingNOMORETHANTHREEWORDSforeachanswer.
CircleFOURlettersA~G.WhichFOURactivitiesoftheUnionarementionedbythespeaker?(A)raisingmoneyforgoodcauses(B)po
Completethetablebelow.WritetheappropriatelettersA-GagainstQuestions36~40.MAINROLES(A
Completethesentencesbelow.WriteNOMORETHANTHREEWORDSforeachanswer.Studentsneedafrontdoorkeybetween【T15】___
Themanwantsinformationoncoursesfor
Themanwantsinformationoncoursesfor
Completethenotesbelow.WriteNOMORETHANTWOWORDSforeachanswer.Researchingtheoriginofmedievalmanus
Writethecorrectletter,A-F,nexttoquestions21-26.AVideoResourceCentreBReadingRoomCFoodServiceCentreDPeriodic
brand该题题目处的rivalproducts表示“竞争对手的产品”。在发展阶段出现的新的竞争对手,销售部门可以做的是使他们的品牌区别于竞争对手的产品。
(Ofthemany)mushroomspecies(growing)wild,thecommonfieldmushroomis(theone)thatismostfrequently(gather)forhuman
随机试题
患者,男性,56岁。货车司机,节律性上腹痛15年,每于进餐后疼痛,餐后2小时左右逐步缓解,胃镜检查确诊为胃溃疡。胃溃疡常见病因中不包括
黄沙百战穿金甲,不破楼兰终不还。穿:
下列疾病中,可产生杵状指的是()
某郊区小学校为方便乘坐地铁,与相邻研究院约定,学校人员有权借研究院道路通行,每年支付一万元。据此,学校享有的是下列哪一项权利?(2010年试卷三第9题)
通过某种图形形式来确定和形象体现项目组织内容组织单元或个人之间相互工作关系的管理工具是()。
《劳动法》规定,不得安排未成年工从事矿山井下、有毒有害、国家规定的( )体力劳动强度的劳动和其他禁忌从事的劳动。
甲商场向乙企业发出采购100台冰箱的邀约,乙企业于5月5日寄出承诺信件,5月8日信件寄至甲商场。适逢其总经理外出,5月9日总经理知悉了该信内容,遂于5月10日电传告知乙企业收到承诺。该承诺的生效时间是()。
根据评价所运用的方法和标准不同来划分,选拔性考试属于()
《中共中央关于加强党的政治建设的意见》就加强党的政治建设作出了多项部署。关于其部署,下列说法中错误的是:
Studentsofeconomicsareinrevoltagain.Thisyear,65groupsofstudentsfrom30countriesestablishedanInternationalStudent
最新回复
(
0
)