1)用于完成时的区别

延续动词表示经验、经历; 瞬间动词表示行为的结果，不能与表示段的时间状语连用。

He has completed the work. 他已完成了那项工作。 (表结果)

I've known him since then. 我从那时起就认识他了。(表经历)

2)用于 till/ until从句的差异

延续动词用于肯定句，表示"做……直到……" 瞬间动词用于否定句，表示"到……，才……"

He didn't come back until ten o'clock.

他到 10点才回来。

He slept until ten o'clock.

他一直睡到 10点。

典型例题

1. You don't need to describe her. I___ her several times.

A. had met B. have met C. met D. meet

答案 B. 首先本题后句强调对现在的影响，我知道她的模样，你不用描述。再次， several times告知为反复发生的动作，因此用现在完成时。

2. - - - I'm sorry to keep you waiting.

- - - Oh, not at all. I___ here only a few minutes.

A. have been B. had been C. was D. will be

答案 A. 等待的动作由过去开始，持续到现在，应用现在完成时。