动词按其动作发生的方式、发生过程的长短可分为延续性动词与非延续性动词。

一、延续性动词

1. 表示能够延续动作的动词，如：learn, work, stand, lie, know, walk, keep, have, wait, watch, sing, read, sleep, live, stay 等。延续性动词可以与表示时间段的状语连用。
2. 表示时间段的短语有: for+ 一段时间, for 2 years; since 从句, since he came here; since+ 时间点名词, since last year, since 5 days ago; how long; for a long time 等。
例: He has lived here for 6 years.
You can keep the book for 5 days.
I stayed there for 2 weeks last year.
How long did you stay there last year?

二、非延续性动词

1. 非延续性动词也称终止性动词、瞬间动词，表示不能延续动作的动词，这种动作发生后立即结束。
如：open, die, close, begin, finish, come, go, move, borrow, lend, buy 等。
2. 非延续性动词在肯定句中与表示时间点的状语连用，如：two years ago; at 5 o'clock
例: He died 5 years ago.
3. 否定的终止性动词可以与表示时间段的时间状语连用。
例: I haven' t left here for 3 years.
I haven' t heard from him for 3 weeks.

三、延续性动词与非延续性动词之间的转换

leave --- be away, borrow --- keep, buy --- have,   begin/start --- be on,   die --- be dead,  finish --- be over,  join --- be in+ 组织机构 , be a member of+ 组织机构 ,  open sth --- keep sth open,  fall ill ---  be ill,  get up---be up,   catch a cold --- have a cold,  come here --- be here, go there --- be there,   become --- be,   come back --- be back,  fall asleep --- be asleep,  get to/ arrive/reach --- be (in),  leave --- be away from,  get to know --- know, go (get) out → be out , put on → wear, catch a cold → have a cold 等。   

例: The old man died 4 years ago.  ----The old man has been dead for 4 years.  
He joined the Party 2 years ago.   -----He has been in the Party for 2 years.    
I bought the book 5 days ago.  ---- I have had the book for 5 days.