11.14 延續(xù)動(dòng)詞與瞬間動(dòng)詞
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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(yǔ)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(lái)。
   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(guò)去開(kāi)始,持續(xù)到現(xiàn)在,應(yīng)用現(xiàn)在完成時(shí)。