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
Asbestos(石棉)is tile generic name for a number of naturally occurring fibrous mineral silicates of which the most common types ar
Asbestos(石棉)is tile generic name for a number of naturally occurring fibrous mineral silicates of which the most common types ar
admin
2015-01-09
24
问题
Asbestos(石棉)is tile generic name for a number of naturally occurring fibrous mineral silicates of which the most common types are crocidolite.also known as blue asbestos,and chrysotile(white asbestos).
Employed for at least 2,000 years.it is valued by industry because of its tensile strength and flexibility,and its resistance to acids,heat and friction. Asbestos has had a very wide variety of applications. It has been commonly employed in the building industry as a fireproofing agent and as a strengthener. The metal frames of buildings were sprayed with an asbestos solution to prevent the spread of fires,while asbestos was routinely mixed in with cement to provide greater resistance to weathering agents. It is also used in motor-vehicle brake linings,gas-mask filters,certain types of talcum power,fire-resistant clothing, corrugated-iron roofing and in water and air pipes. As a result of such wide employment.it is likely that most people have been exposed to at least a small quantity of asbestos fibers.
During inhalation,all particles which enter the respiratory tract pass through a series of filter mechanisms. Particles are filtered out at different points of the respiratory tract depending on their size. The smaller the particle,the further into the respiratory it may penetrate before being arrested. The first set of filters consists of the hairs and mucons(粘液的)lining of the nose and mouth which prevent the entry of larger particles. When large particles are inhaled,they stimulate this mucous lining,which results in coughing and the consequent expulsion of the particles. The mucous lining extends downwards through hair-lined bronchial(支气管的)tubes of increasingly fine diameter which further filter the air before it reaches the respiratory bronchioles,a series of very fine tubes attached to air exchange chambers known as alveoli(肺泡). The alveoli are composed of a thin layer of ceils through which oxygen passes into blood vessels and is then distributed to the blood-stream.
Particles smaller than eight micrometers may reach the alveoli. This is the case with blue asbestos particles,which are very straight and slender and tend not to be arrested by mucous and expelled. As a result,they may reach the alveoli and penetrate the delicate cells lining the wails.
Some asbestos fibrils(particles)which reach the alveoli may be surrounded by scavenger cells known as macrophages,which serve to remove the fibrils from the body by expectoration(吐痰)or excretion. Other particles may remain in the alveoli with no adverse effects in case where the asbestos particles have penetrated the alveolar wall,scar tissue develops. This reduces the effectiveness of the alveoli and so less oxygen passes into the blood and less carbon dioxide is removed from it. This condition is known as asbestosis(石棉沉滞症). The process of scarring may take place gradually and the disease may not be diagnosed until 20 or 30 year after the initial exposure.
Directions: The passage below summarizes the main points of the passage. Read the summary and then select the best word or phrase from the box below, according to the passage. You should decide on the best choice and mark the corresponding letter on the Answer Sheet with a single line through the center.
[*]
Due to its versatility,asbestos has been【R1】______since ancient times in a wide range of【R2】______When asbestos【R3】______are【R4】______they pass through a series of【R5】______which arrest their【R6】______The stimulation of【R7】______causes【R8】______which expels them from the respiratory tract, If particles are very【R9】______.which is the case with【R10】______asbestos,they may【R11】______as far as the alveoli. Some of these particles may【R12】______the alveolar wall and cause【R13】______to develop,This reduces the【R14】______of the lung and causes the condition known as【R15】______.Symptoms of the disease may take up to【R16】______to appear.
Directions: The previous passage is to be continued by the following passage about asbesto-related diseases, in which four phrases have been left out. Read the passage and select the best phrase from the box for each gap. You should decide on the best choice and mark the corresponding letter on the Answer Sheet with a single line through the center.
[*]
The inhalation of asbestos particles is associated with a number of lung diseases such as asbestosis and lung cancer. Asbestosis is caused by the entry of asbestos particles into the walls of the alveoli , 【R17】______. The lung loses its elasticity and may change shape. The initial symptoms of asbestosis are a tightness in the chest and breathlessness. In its later stages,sufferers 【R18】______.
Lung cancer,the generic term for malignant tumors of the alveoli and bronchial tubes,has been shown to be directly related to the inhalation of asbestos particles. As in the case of asbestosis,there is generally a period of latency【R19】______.despite the absence of further exposure. Research suggests that there is a direct correlation between the degree of exposure to asbestos and the incidence of lung cancers. Where exposure occurs,the level of risk is further increased by cigarette smoking. Asbestos workers who smoke cigarettes have a 90% greater risks of contracting lung cancer than workers who do not smoke.
Exposure to blue asbestos has been shown to produce mesothelioma,a rare cancer of the outer lining of the lung or pleura. In a normal population【R20】______. Where epidemiological surveys have revealed a higher incidence of the disease.it is almost always related to asbestos exposure.
【R17】
选项
答案
F
解析
空格前句子大意为:石棉沉滞症是由石棉分子进入血管壁而引起的;空格后的句子大意为:肺失去了弹性并可能改变形状。通过这两句话可知,正确答案为F。
转载请注明原文地址:https://kaotiyun.com/show/GfQO777K
0
考博英语
相关试题推荐
TheJapanesedesireformarriagehadbeenverystrong,Inthefifth"worldyouthattitudesurvey"【C1】______bytheManagementand
TheJapanesedesireformarriagehadbeenverystrong,Inthefifth"worldyouthattitudesurvey"【C1】______bytheManagementand
Fromtheperspectiveofthepoor,itseemsobviousthatthebenefitswouldoutweighthecosts.Thebenefitstopoorpeopleofno
Manymentalinstitutionsthroughoutthecountryhavebeenturnedintodumpinggroundsforthousandsofoldsterswhohavenoplac
AnumberofbookslikeReadingFacesandBodyLanguagehave【C1】______theindividual’stendencytobroadcastthingsthroughallm
Theconferenceappealedtotheinternationalcommunitytojointly_____theissueofglobalwarming.
WhenDonaldarrivedforhisfirstgroup-therapysessionhewasinawheelchair,sufferingfrommalignantmelanomaandseverelyd
Thetopexecutiveswereaccusedoftellinghalf-truthsandeven______liesaboutthecompany’sfinancialconditions.
ThecustomoftheChristmastreeisbelievedtohavebegunbyMartinLutherinGermany.AThesightofaevergreentreeonChrist
Thedifferencebetweenaliquidandagasisobvious【1】theconditionsoftemperatureandpressurecommonlyfoundatthesurface
随机试题
使用铬黑T最适宜的酸度是pH值()。
A、子宫肌瘤较小,无症状或已近绝经期B、宫颈原位癌C、晚期子宫内膜癌D、单个较大肌瘤E、绝经期前后的卵巢癌全子宫切除术适于
属宫颈癌的癌前病变是
室性心动过速心电图诊断的最主要依据是
(2012年)压气机压缩制气过程有三种典型过程,即等温过程、绝热过程和多变过程,在同样初始条件和达到同样压缩比的条件下,三者耗功量之间的正确关系为()。
某化学品经营企业从化工厂购进一批(10t)氢氧化钠(固碱),存放在一座年久失修的库房中。一天晚上,大雨倾盆而下,库房进水。氢氧化钠泡在水中,部分泡在水中的氢氧化钠开始深入水中并顺水流入地沟。仓库保管员发现后,及时报告了单位主管领导。根据以上场景,回
在下列有关网络计划的叙述中,正确的提法有()。
证券交易所每年应对从事证券经纪业务的会员的()方面进行抽样或者全面检查,并将检查结果报告中国证监会。
方程有实根.(1)实数a≠2(2)实数a≠一2
运行下列程序,输入数据8、9、3、0后,窗体中显示结果是PrivateSubForm_click()DimsumAsInteger,mAsIntegersum=0Dom=InputBox(“输
最新回复
(
0
)