2017年大学英语四级阅读寒假练习题(18)思维导图
英语四级阅读理解是英语四级考试中的重点部分，而随着时代的发展，英语四级中的阅读题型也在不断更替改变，下面是小编为大家整理的英语四级阅读寒假练习题，希望可以为大家带来帮助。
树图思维导图提供 2017年大学英语四级阅读寒假练习题(18) 在线思维导图免费制作，点击“编辑”按钮，可对 2017年大学英语四级阅读寒假练习题(18) 进行在线思维导图编辑，本思维导图属于思维导图模板主题，文件编号是：7bcd8f64dfddbe037151c9043a817aed
思维导图大纲
2017年大学英语四级阅读寒假练习题(18)思维导图模板大纲
2017年大学英语四级阅读寒假练习题汇总
Someradiosingalswereheardin1967.Theywerecomingfromapointintheskywheretherewasunknownstar.Theywerecomingveryregularly,too:aboutonceasecond,iftheywerecontrolledbyclock.
Thescientistswhoheardthesignalsdidnottellanybodyelse.Theywereratherafraidtotellincasetheyfrightenedpeople.Thesignalswerecomingfromaverysmallbody—nobigger,perhapsthantheearth.Wasthatwhynolightcouldbeseenfromit?Orwerethesignalscomingfromaplanetthatbelongedtosomeotherstar?Therewasnoendtothequestions,butthescientistskeptthenewssecret.“Perhapsthereareintelligentbeingsoutthere.”theythought,“whoaretryingtosendmessagestootherplanets,ortous?Sothenewswasnotgiventothenewspaper.Instead,thescientistsstudiedthesignalsandsearchedforotherslikethem...Well,allthathappenedin1967and1968.Sincethenscientistshavelearntmoreaboutthosestrange,regular,radiosignals.Andtheyhavetoldthestory,ofcourse.
Thesignalsdonotcomefromaplanet;theycomefromanewkindofstarcalleda“pulsar””.Aboutahundredotherpulsarshavenowbeenfound,andmostofthemareverylikethefirstone.
Pulsarsarestrongradiostars.Theyarethesmallestbuttheheavieststarsweknowatpresent.Ahandfulofpulsarwouldweighafewthousandtons.Theirlight—iftheygivemuchlight—istoosmallforustosee.Butwecanbesureofthis,nointelligentbeingsarelivingonthem.
21.Theradiosignalsdiscussedinthispassage____.
A.wereregularB.werecontrolledbyaclock
C.wereheardin1967onlyD.weresecretmessages
22.Theradiosingalsweresentby____.
A.asatelliteB.aplanet
C.askybodywhichwasunknownatthattime
D.intelligentbeingswhowereunknownatthattime
23.Thescientistsdidnottellpeopleaboutthesignalsbecause____.
A.thesingalsstoodforsecretmessages
B.peoplewouldaskthemtoomanyquestions
C.theydidnotwanttofrightenpeople
D.theystoodforunimportantmessages
24.Apulsaris____.
A.asmallheavystarwhichsendsoutstrongradiosignalsandcannotbeseen
B.asmallheavyplanetwhichsendsoutstrongradiosignalsandcannotbeseen
C.asmallheavysatellitewhichsendsoutstrongradiosignalsandcannotbeseen
D.asmallintelligentbeingwhosendsoutstrongradiosignalsandcannotbeseen
25.Whichofthefollowingistrue?
A.Oneofthepulsarsfoundbyscientistssendsradiosignals.
B.Pulsarbegantosendradiosingalsin1967.
C.Scientistshavesearchedforpulsarsformanyyearsbutfoundnone.
D.Scientistshavefoundmanypulsarssince1967.
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