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
自考
In our day of the automobile and paved highway few people ever encounter quicksand(流沙). Yet quicksand is still common in many pa
In our day of the automobile and paved highway few people ever encounter quicksand(流沙). Yet quicksand is still common in many pa
admin
2011-01-31
64
问题
In our day of the automobile and paved highway few people ever encounter quicksand(流沙). Yet quicksand is still common in many pans of the country. It may be more dangerous for being less familiar.
Quicksand is usually found along the shores and in the beds of rivers. It is simply sand saturated(使饱和)with water from beneath,as from a spring. The water flowing into the sand separates the grains. The suspended grains give rather easily and a heavy object placed on the surface is likely to sink. How fast it sinks depends on its weight and surface area.
How does one detect quicksand? It cannot be done by the eye alone,since sand which looks firm may suddenly collapse and trap anyone who ventures out on it. The only way to be sure is to test the sand before walking on it. For test a probing(探索)pole or long stick should be used. If the pole sinks more than six inches,the sand is probably quicksand.
A traveler who stumbles into quicksand will soon sink to the depth of his knees. If he stands still or struggles wildly,he will sink even further. He should at once lie on his back and stretch out his arms. Contrary to popular notion,quicksand does not suck objects down,and will support more weight than water alone. While the trapped person“floats”on the surface of the sand,rescuers should build a platform with boards or branches. Then they can pull him out slowly.
If the trapped person is alone,he can rescue himself. When he is in the floating position,he should begin rolling toward solid ground. Rolling is the only way of getting free. It should be done with frequent rests,so that the trapped person does not tire himself. When he reaches solid ground,he should swing his legs to safety,and quickly scramble out of the quicksand.
The main idea of this passage is______.
选项
A、that today few people ever encounter quicksand
B、that quicksand is still common in many parts of the country
C、that quicksand cannot be detected by the eye alone
D、expressed by none of the above
答案
D
解析
A,B,C三选项点到但均未深入,故选D。
转载请注明原文地址:https://kaotiyun.com/show/fVAR777K
本试题收录于:
英语(二)题库公共课分类
0
英语(二)
公共课
相关试题推荐
Americansareaveryenergeticandmobilepeople,alwaysontherun,rushingfromoneappointmenttoanother,fromaPTA(Parent-Tea
Curiosityisnotonlyapossiblemotivation,itisalsoagreathelpinyourlearninglanguages.Rememberthatalanguageisnot
ImethimontheInternetandwechattedforseveralmonths.EverytimeIsuggestedwemeetinperson,hewouldcomeupwithane
Theiraimwasto______(modem)thehealthservice,andtheysucceeded.
Teachers______theirstudentstobeusefultosocietyinthefuture.
Idon’twant______whileinasecondsleepevenifsomethingserioushappens.
Aswitnesses(证人)totheaccident,wewereaskedtomakewritten______(declare)ofwhatwehadseen.
DuringtheChristmasshoppingrushinLondon,astorywasreportedofatramp(流浪者)who,apparentlynofaultofhisown,foundhim
IncomeIncomemaybenationalincomeandpersonalincome.Whereasnationalincomeisdefinedasthetotalearnedincomeofa
随机试题
Itisclearthatsomepeoplewhoparticipateinexercisetrainingwilldevelopinjuriestotheirbones,muscles,andjoints(关节)
Howwelldoyouknowyourdog?Theansweris,notnearlyaswellasyourdogknowsyou.Giventherightmotivation,humanscanc
People’sattitudes【C1】______gift-givingmay【C2】______fromcountrytocountry,【C3】______thedesiretoconveyafeelingoffrie
下列哪一方法不属于家校教育相互配合的方法?()
分成地租是指租佃农民按照农田收获量的一定比例向地主缴纳地租。根据上述定义,下面属于分成地租的是:
活动课程夸大了儿童的个人经验,忽视了知识本身的逻辑顺序,影响了系统知识的学习,所以其容易导致教学质量的降低。()
简述性陈述性知识与程序性知识的联系和区别。
(1,1,1).令则所以
Wesufferfromaconspicuouslackofrolemodelsandsharedcauses.Thisis【B1】______ofreason,Ithink,thatmanyyoungAsian-A
BanonPublicSmoking1.GoalinspeakingAbanofsmokingfrom【T1】【T1】______2.Causeofillnessesand【T2】【T2】______Riskofhe
最新回复
(
0
)