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。
