know 是不是瞬间动词?Susan and Jenny are pen pals.They _________ each other for about two years.A) knew B) had known C) will know D) have known我选的是A.可是答案是D.所以求解释,know是瞬间动词还是延续性动词?

know 是不是瞬间动词?Susan and Jenny are pen pals.They _________ each other for about two years.A) knew B) had known C) will know D) have known我选的是A.可是答案是D.所以求解释,know是瞬间动词还是延续性动词?
know 是不是瞬间动词?
Susan and Jenny are pen pals.They _________ each other for about two years.
A) knew B) had known C) will know D) have known
我选的是A.可是答案是D.所以求解释,know是瞬间动词还是延续性动词?

know 是不是瞬间动词?Susan and Jenny are pen pals.They _________ each other for about two years.A) knew B) had known C) will know D) have known我选的是A.可是答案是D.所以求解释,know是瞬间动词还是延续性动词?
解释为“认识”的时候 就可以延续用
解释为“知道”的时候 就数瞬间动词

这里是说他们认识(相互了解)了两年
如果是they knew each other 那么就不能用for 了，要说 two years ago.

解释为“认识”的时候 就可以延续用
解释为“知道”的时候 就数瞬间动词
现在完成时可以用来表示发生在过去某一时刻的,持续到现在的情况,常与for,since连用.