现在完成时可表示持续到现在的动作或状态，动词一般是延续性的，如live, teach, learn, work, study, know.

过去时常用的非持续性动词有come, go, leave, start, die, finish, become, get married等。

举例：

I saw this film yesterday.

(强调看的动作发生过了。)

I have seen this film.

(强调对现在的影响，电影的内容已经知道了。)

Why did you get up so early?

(强调起床的动作已发生过了。)

Who hasn’t handed in his paper?

(强调有卷子，可能为不公平竞争。)