6. 终止性动词appear, begin, set up, buy, die, join, start, come, fall, finish, leave, lend, sell, lose, stop, etc.的完成时不能与for连用。
不能说：He has got up for 2 hours.
只能说：He got up 2 hours ago.
He has been up for 2 hours.
It is 2 hours since he got up. 来源：考试大
7. by + 将来时间状语用将来完成时，by + 现在时间状语用现在完成时。
By this time next year we’ll have graduated.
By now I have seen the film three times. 来源：考试
(四)过去完成时
1. by + 过去时间状语用过去完成时。
By last year I had learned 2000 English words.
2. 在no sooner … than, hardly … when, scarcely … when, barely … when等句型中，主句中的谓语用过去完成时，从句中的谓语用过去时。
No sooner had we got all the crops in than it began to rain.
She had hardly finished his speech when the audience started cheering.
