has been over你能告诉我这样写的原因吗？你这三个空伤脑筋啊。只能用完成时来表示先后关系了，完成放学，再回家。例如： You can go to play basketball after you have finished your homework.很高兴为你解答！老师祝你学习进步！望采纳，多谢你的问题！^_^