延续性动词和非延续性动词的用法
1、现在完成时表示动作从过去某个时候开始一直持续到现在，而与一段时间连用时应注意
句中的谓语动词必须是延续性动词，非延续性动词不可以和一段时间连用。

我离开家乡我离开家乡已有10 年了
误： I have left my hometown for 10 years.
正： I have been away from my hometown for 10 years.
我买这本书已有两天了。

误： I have bought this book for two days.
正： I have had this book for two days.
2、在否定句中，非延续性动词可与一段时间连用。

I haven’ t gone to see him for several months.
我已经好几个月没去看他了。

3、在肯定句中非延续性动词与表时间段的状语连用时可采用下述三种方法：
a．将非延续性动词转化为延续性动词
非延续性动词延续性动词非延续性动词延续性动词
buy have borrow keep
open be open close be closed begin/start be on come be here go be there finish be over
die be dead catch a cold have a cold
put on wear get up be up
wake up be awake fall asleep be asleep
lose not have join be in
leave be away arrive/reach be
b．将时间状语改为过去时间，且用一般过去时代替现在完成时。

c．用句型“It ’ s时+间段 + since 从句（从句的非谓语动词用非延续性动词的过去式）”表示。

It is two years since the old man died.
这个老人已经去世两年了。