something must be done to pretect our enviroment.must后面为什么接done.而不能接doing请详解哦

there must be something you can do 中文意思是什么 something must do,something must not do must 加to There must be something wrong. Christmas must be something mo at present there must be nothing we can do to prevent the juvenile crimes怎么不用something that we can do和something which we can do there must be something wrong to it It must be something like it. you must be something to talk be up to do something We must do something.This is something.Therefore,we must do this.这话该如何解释 We must do something before it'll be too late.改错,这句话哪里错了,找出语病! something must to be done和something must be done区别 don't need you,though i'm alone!Now ,i just want to do some thing i must do.forget something.forget someone!To be simple. 是must be to do还是must be doing must be do与must be doing 区别 Something ______ to help the people in Egytian ferry disaster.A.can do B.must be done C.must do D.should do为什么选C 简单说下理由,长的不要.正确答案是B be+形容词(difficult) to do something造句 be out to do something是什么意思?