三道初中英语单选
1.Ifeveryonemakesacontribution_______theenvrionment,ourcountrywillbecomemorebeautiful.
A.toprotectB.inprotecting
C.toprotectingD.forprotecting
2.Manypeoplewelcomethe"Harm-freeInternet",butwhatdomanyschoolstudents_______it.
A.hearofB.thinkof
C.lookoverD.talkabout
3.-Timetogotobed,mary.
-Oh,Mum,lwon'tgotobed_____Ihavefinishedmyhomework.
A,afterB.sinceC.untilD.assoonas
第二个请解释一下