to do →to be done to be doing to have done →to have been done 动词不定式的用法,这几个怎么回事?
问题描述:
to do →to be done to be doing to have done →to have been done 动词不定式的用法,这几个怎么回事?
答
to do →to be done to be doing to have done →to have been done 动词不定式的用法,这几个怎么回事?