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。)

　　She has returned from Paris.

　　她已从巴黎回来了。

　　She returned yesterday.

　　她是昨天回来了。

　　He has been in the League for three years.

　　(在团内的状态可延续)

　　He has been a League member for three years.

　　(是团员的状态可持续)