当非谓语表示的动作发生在主句的谓语动词所表示的动作或状态之前已经完成时用非谓语的完成式。如: Having dong the homework, he went home.做完作业在回家之前。 Having finished the job,we had a rest. I was sorry to have kept you waiting.追问
考试中怎么分清什么时候有done 什么时候用having done 的形式
追答
done 常常表示“已经完成,被动”; having done 只表示“已经完成”,1在介词后,2或者要求跟ing做宾语的词后边;或者3强调前一个ing(having done)短语表示的动作在后一个之前。比如上边所给的两句。