延续性动词表示的动词是一种延续的动作,这种动词可以延续下去或产生持久的影响.如：learn,work,stand,lie,know,walk,keep,have,wait,watch,sing,read,sleep,live等.
终止性动词也称非延续性动词、瞬间动词,表示的动作不能延续,即动作发生立即结束,产生某种结果.在有了某种结果之后,就不能再继续下去.如：leave,start,set out,arrive,reach,get to,begin,stop,shut,turn off,marry,put,put on,get up,wake,fall,join,receive,finish,end,complete,become,come,go,die,close,open,break,give,jump,buy,borrow等.
用延缓性动词代替终止性动词.
eg.He has gone to the Internet for six hours.(wrong)
应改为:He has been on the Internet for six hours.
但须注意：终止性动词的否定式可以和since 或for 引导的时间状语连用.因为终止性动词的否定表示的是一种可以延续的状态.
eg.I have heard from my friend in Africa for half a year.(wrong)
I haven’t heard from my friend in Africa for half a year..(right)