八下英语选词填空before,discover,fast,in,come,watch,so,fast,it,ago,shine,notcanLighttravelsataspeedwhichisaboutamilliontimes()thanthatofsound.()onesecond,lidhttravelsabout300,000kilomemters,butsoundtravesonly340m

　　八下英语选词填空

　　before,discover,fast,in,come,watch,so,fast,it,ago,shine,notcan

　　Lighttravelsataspeedwhichisaboutamilliontimes()thanthatofsound.()onesecond,lidhttravelsabout300,000kilomemters,butsoundtravesonly340meters.Youcangetsomeideaofthisgifferenceby()thestartofarunningmatch.Ifyoustandfarawayfromthestarter(发令员),youcanseesmoke()fromhisgun()thesoundreachesyourears.

　　Thefastspeedoflightproducessomestrangefacts.Theneareststaris()farawaythatlightwhichyoucanseefromittonightstartedtotraveltoyouryears()ataspeedofnearlytwomillionkilomemterseveryminute.Thelightfromsomeoftonight'sstartedon.()journeytowardsyouevenbeforeyouwereborn.

　　So,ifwewanttobehonest(诚实）,we()say,"Thestarsareshiningbrightlytonight."Wehavetosay,"Thestarslooknice.theywere()fouryearsagobuttheirlighthasjustreachedourearth."