完形填空。Theworld1manyinterestingsounds.Someareunpleasanttoourearswhile2areverypleasanttohear.Inasingledayyouprobablyhear3sounds.Allsoundsaredifferent.Some4loud,somesou

　　完形填空。

　　Theworld 1 manyinterestingsounds.Someareunpleasanttoourearswhile 2 areverypleasant

　　tohear.Inasingledayyouprobablyhear 3 sounds.Allsoundsaredifferent.Some 4 loud,some

　　soundsarehigh,othersarelow,somesoundsareuseful. 5 soundwecannottalkorlistentoeachother.

　　Theringingofthealarmclockwakespeopleup;thehootingofacarwarnspeopleofdanger.

　　Somesoundsareharmful.Whenplanesflylow 6 theland.Theveryloudsoundscandamagethehouse.

　　Veryloudsoundcanevenmakepeopledeaf.Weknowsoundtravelsaboutonekilometerinthree 7 .Ina

　　thunderstormyouseethelightingfirstandthenhearthethunder.

　　Thisisbecauselighttravels_8_thansound.Nexttimeyouseelightning,countthenumberofseconds

　　beforeyouhearthethunder.

　　Dividethisnumber 9 3. Thiswilltellyou 10 kilometersawaythethunderstormis.

　　( )1. A.fullof

　　( )2. A.others

　　( )3. A.hundredsof

　　( )4. A.may

　　( )5. A.of

　　( )6. A.in

　　( )7. A.hours

　　( )8. A.morefast

　　( )9. A.in

　　( )10. A.howmach B.fillwith

　　B.theother

　　B.hundredof

　　B.Maybe

　　B.with

　　B.on

　　B.days

　　B.muchfaster

　　B.of

　　B.howmany C.isfilledof

　　C.another

　　C.Hundreds

　　C.maybe

　　C.without

　　C.above

　　C.minutes

　　C.morefaster

　　C.by

　　C.how D.isfilledwith

　　D.theothers

　　D.hundred

　　D.can

　　D.By

　　D.over

　　D.seconds(秒)

　　D.muchfaster

　　D.at

　　D.howlong