all that can be done has been done 为什么要用has,不用have

all that can be done has been done. all that can be done been done.why is all that?没有that不行吗? all that can be done has been done.中的that为all that can be done has been done.中的that为什么不能用which替换? all that can be done has been done为什么用HAS all that can be done has been done 为什么要用has,不用have All that can be done __been done.请问该用has还是 have? They won't leave until all that can be done is done 合并句子all can be done.all must be done _ can be done has been done.A.All B.All that C.All what D.Anything They came to the conclusionn.________ by a computer.A.that not all things can be done B.because of not all things be doneC.being not all things can be done D.because not all things can be done 19.All that can be done .　　A.have been done B.have done C.has been done D.has done顺便,翻译一下这句话吧 that,can,be,all,that,done,is 组句 并说出意思 all ( ) can be done must be done.A.that B.which C.who D./如题,说明理由 can be done has been Everything that can be done has been done 中can be done has been done All that can be done___A.have been done B.have done C.has been done D.has done为什么选C怎么解释? All that can be done___________A.has done B.has been done C.have done D.have been done 请选入合适的选项.并解释原因, —How are things getting on?—All that can be done____.A.has been done B.have been done C.has done D.have done All that can be done is to convert energy from one form into another.