Hand in your paper,if you____your answer.填finish还是have finished
问题描述：
Hand in your paper,if you____your answer.填finish还是have finished
答
Hand in your paper,if you____your answer.
填have finished
条件或时间等状语从句,从句的谓语动词发生在将来 可用do或havedone
填have done 是强调 从句动作先于主句的谓语动词所表示的动作发生
如：don't get off until the bus has stopped.