现在时
I have finished my homework.
I had finished my homework by 10:00 this morning.
概
现在完成时1.表示过去发生的对现在有影响的动作；  I have seen the film many times. 2.表示过去某一时间开始一直延续到现在的动作。  He has lived here since 1949.过去完成时  表示过去某