all the things should be done have been done already

all the things should be done have been done already I am satisfied _ should be done has been already done.A.what all that can be done been done. can't be done.should be done.should have done all things have been already must have been done/must be done have been done 和 to be done should have done与should have been done的区别? all that can be done has been done 为什么要用has,不用have All the work (has/have) been done successfully,选哪个? 在all that should be done has been done用了has,但在all that shoul Has____could be done been done to save the injured.A.all B.w