延续性动词与非延续性动词及其转换
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.延续性动词表示能够延续的动作,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。

表示时间段的短语有: ⑴for+一段时间, 如：for 2 years; ⑵since从句, 如since he came here; since+过去时间点名词, 如since last year, since 5 days ago。

例: He has lived here for 6 years.
You can keep the book for 5 days.
二.非延续性动词也称终止性动词、瞬间动词, 表示不能延续的动作,这种动作发生后立即结束。

如:open, die, close, begin, finish, come, go, move, borrow, lend, buy等。

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.
三.延续性动词与非延续性动词之间的转换：（考试重点）
例：He left five minutes ago. = He has been away for five minutes.
这句话的意思是指他离开的动作是5分钟之前发生的，是过去时。

也就是说从他离开到现在已经有五分钟了，这个动作是延续的，要用现在完成时，并且要把原来的短暂性动词改为延续性动词。

一些短暂性动词及相应的延续性动词：
arrive（get to /reach）→ be here (in)
begin(start) → be on
die → be dead
come here（back）→be here（back）
leave → be away (from)
fall ill(sick, asleep)→be ill(sick, asleep)
get up→ be up
go/ get out（there）→ be out（there）
finish → be over
put on → wear 或be on
open → be open（keep sth. open）
join → be in或be a member of…+组织机构
close → be closed
go to school → be a student
borrow →keep
buy/get →have
catch(a cold) → have(a cold)
get to know → know begin to study → study come to work → work move to → live in finish → be over come to → be in
sit down → be seated marry → be married dress → be dressed become → be。