【MissWhitehasworkedintheschoolformanyyears.Thestudentsalllikeher.Sheisateacherofchemistry.She_1___chemistryfromthelowesttothehighestgradesintheschool.Sometimesthelowergradeslearnquickly,butsometimestheyarevery2】

　　MissWhitehasworkedintheschoolformanyyears.Thestudentsalllikeher.Sheisateacherofchemistry.She_1___chemistryfromthelowesttothehighestgradesintheschool.Sometimesthelowergradeslearnquickly,butsometimestheyarevery2,andthenMissWhitehastorepeat(重复)thingsmanytimes.

　　Thisyear,thefirstgradestudentshavebeenstudyingchemistryfor3weeks.OnedayMissWhiteaskedthestudents,”Whatiswater?4knows?”Therewasasilenceforsomesecondsand5sad.Justthenonestudentraisedhis6.“Yes,Nick?”saidMissWhiteencouragingly（鼓励地）.Heisnotoneofthecleverestchildrenintheclass,soshewas7thathecouldanswer.“Waterisaliquid(液体)whichhasnocolouruntilyouwashyourhandsinit,”1.A.learnsB.helpsC.teachesD.tells2.A.freeB.slowC.easyD.tired3.A.afewB.alittleC.fewD.little4.A.WhatB.WhichC.WhoseD.Who5.A.thoughB.heardC.feltD.sounded6.A.headB.legC.handD.hair7.A.sadB.happyC.badD.great