1) 用于完成時(shí)的區(qū)別

　　延續(xù)動(dòng)詞表示經(jīng)驗(yàn)、經(jīng)歷; 瞬間動(dòng)詞表示行為的結(jié) 果，不能與表示段的時(shí)間狀語連用。

　　He has completed the work.　　他已完成了那項(xiàng)工作。 (表結(jié)果)

　　I've known him since then.　　 我從那時(shí)起就認(rèn)識(shí)他了。(表經(jīng)歷)

　　2)　用于till / until從句的差異

　　延續(xù)動(dòng)詞用于肯定句，表示"做……直到……" 瞬間動(dòng)詞用于否定句，表示"到……，才……"

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

　　他到10 點(diǎn)才回來。

　　He slept until ten o'clock.

　　他一直睡到10點(diǎn)。

　　典型例題

　　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. 首先本題后句強(qiáng)調(diào)對(duì)現(xiàn)在的影響，我知道她的模樣，你不用描述。再次，several times告知為反復(fù)發(fā)生的動(dòng)作，因此用現(xiàn)在完成時(shí)。

　　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. 等待的動(dòng)作由過去開始，持續(xù)到現(xiàn)在，應(yīng)用現(xiàn)在完成時(shí)。