延续动词与瞬间动词
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.
以上参考自《英语语法精解书籍》