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
54
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 can be inferred from this?
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、Sometimes natural air pollutants can purify air.
B、Natural air pollutants are harmful to people.
C、There are some chemical reactions in the air.
D、Air pollutants move from air to water or soil.
答案
A
解析
本题为推论题。题目问:根据这一段所听到的,能得出什么推论?这一段提到:“当地球发生进化时,这些污染物的浓度就已被各种各样的化学反应所改变,成为生物地理化学成分,然后化合物从空气中转移到水和土壤中,形成净化空气系统”,由此推出A项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/v1fO777K
0
托福(TOEFL)
相关试题推荐
CompletethenotesbelowusingNOMORETHANTHREEWORDSforeachanswer.
CompleteMartin’snotes.UseNOMORETHANTHREEWORDSforeachanswer.CommerciallygrownbananaplantEachbananatreeproduc
Completethenotesbelow.UseNOMORETHANTHREEWORDSforeachanswer.Therearemanykindsofbicyclesavailable:racingtou
WhichTWOofthefollowingcanyougetadviceaboutfromtheUnion?(A)immigration(B)grants(C)medicalproblems(D)personalpro
WhatisthesubjectofTim’sfirstlecture?
Whichcolumnofthebarchartrepresentsthefiguresquoted?
Writethecorrectletter,A-F,nexttoquestions21-26.AVideoResourceCentreBReadingRoomCFoodServiceCentreDPeriodic
Choosethecorrectanswer,A,BorC.Themechanismsforwatermanagementare
Completethesentencesbelow.WriteNOMORETHANTWOWORDSforeachanswer.Themanfeltsatisfiedwith______becauseitwasqu
A、Theimportanceofanthropologytomodernsociety.B、Agoodsourceofinformationaboutasociety.C、Attitudestowardculturei
随机试题
日本的军事战略由内向型的“专守防卫”战略,向外向型的“______”战略转变。()
若∫f(x)dx=xe-x+C,则f(x)=【】
A.肠壁铺卵石样B.线样征象C.跳跃征象D.铅管征象溃疡性结肠炎的X线表现特征是
一般药物的有效期是
为实施9年制义务教育而编写出版教科书,除作者事先声明不许使用的外,在教科书中汇编其已经发表的作品时,可以不经著作权人的许可,也可以不向著作权人支付报酬。()
桃、杏、李、梨、桔被称为花木五果。()
如何解决教师角色冲突?
假如你是单位中负责审批工作的人员。有一次。你要到外地出差。出差前你委托一位同事替你处理审批事务。你回来之后发现,其中的一个审批。申报人的材料不完备。但是。你所委托的同事在审查日寸不够认真,最后让他审批通过了。这个失误可能会带来不好的后果。对于这种情况。你会
没有一个植物学家的寿命长到足以研究一棵长白山红松的完整生命过程。但是,通过观察处于不同生长阶段的许多棵树,植物学家就能拼凑出一棵树的生长过程。这一原则完全适用于目前天文学对星团发展过程的研究。这些由几十万个恒星聚集在一起的星团,大都有100亿年以上的历史。
某公司拥有IP地址块202.113.77.0/24。其中202.111.77.16/28和202.113.77.32/28已经分配给人事部和财务部,现在技术部需要100个IP地址,可分配的IP地址块是:
最新回复
(
0
)