have been done 这个短语要是在句子中,哪个词是谓语动词?

have been done 这个短语要是在句子中,哪个词是谓语动词? must have been done must have done have been done 这个是什么时态的结构 有没有been done 这个时态?注意,没有have to have been done 有这个形式吗? have been done 和 to be done Mr.Page will have been teaching for a total of forth years.在这句话中,我想知道为什么要用will have been teaching(will have been doing)这个时态,而不是will have teached(have been done) have been done 语法呢 has been doing have been done区别 being done,have been done和having done怎么分辨 HAVING BEEN DONE和HAVE BEEN DONE有什么区别? could have been done ,could have have done 与have been done的区别 have done和have been done 的区别, have been done 是什么时态?那have done呢? should have done与should have been done的区别? since前用have done 还是have been done have done和have been done的用法是什么?