单元清•阅读理解。•A•Haveyoueverheardanechoofyourvoice?•Anechoisareflected(反射)sound.Standinaverylarge,emptyhallwithnothingonthewalls.Thenshout.Thesoundsyoumakewillhitthewallsandcomebacktoyou.Thewallsreflectthesounds.Thesereflectedsoundsarecalled“echoes”.•Wecanusereflectedsoundtomakesoundtravelfarther.Holdawatchaboutfiftycentimetersfromyourear.Youcannothearit.Thesoundofthewatchtravelsashortwayinalldirections.Itdoesnottravelasfarasyourear.Youcanmakeittraveltoyourearbyusingarollofcardboard(纸板筒).•Maketherollofcardboardaboutfiftycentimeterslong.Putoneendoveryourearandholdthewatchattheother.Nowyoucanhearthewatchbecausethesoundhasnotgoneinalldirections.Itisreflecteddowntherolltoyourear.•Amegaphone(喇叭筒)worksinthesameway.Itmakessoundtravelfarther.Itreflectsthesoundintoabeamwhichcantravelalongway.Intheship,thesailorusesthemegaphonetomakehisvoicetravel.Withoutthemegaphone,hisvoicecannottravelfar.•Weusereflectedsoundinmanyways.Weuseittomeasurethedepthofthesea,forexample.Amongtheanimals,batsandwhalesusereflectedsoundtotellthemwheretheyareandwhatthingsarenearthem.•1.Whatiscalled“echo”？•A．Thesoundthatismadebymanoranimalscomesbackfromsomeplace.•B．Veryloudvoicesthataremadebyman.•C．Veryloudvoicesthataremadebyanimals.•2.Wecanhearourechoesifwe________．•A．shoutinasmallroom•B．shoutinalargehousefullofthings•C．shoutinnarrowvalleys(山谷)•3.Fromthetextwelearnthat________.•A．reflectedsoundisusefulonlytoblindpeople•B．peoplehaven'tmadeuseofreflectedsoundyet•C．batsusereflectedsoundtoflyandgetfood•4.Ifyouhaven'tgotamegaphone,________willhelpyoutomakeyourvoicetravelfarther.•A．alongpieceofwoodB．arollofcardboard•C．athinthreadACCB•B•AndywasstilltravelinginSpainwhenherealizedhehadtoconfirm(确认)his__①__withtheairlinecompany.HewasvisitingSpaininordertoimprovehisSpanish.When_he_was_speaking_to_people_face_to_face,_he_had_no_difficulty_understanding_what_they_said.However,whenhewasspeakingonthephone,hestillhadaproblem.Andycalledtheairline.Andtheclerkc...
