Question

在现在完成时中，非延续性动词什么时候变为延续性动词

Answer 1

现在完成时可以和带有since或for等表示“一段时间”的状语连用,表示动作或状态从某一时刻开始，一直持续到现在。

如：I haven't seen him for two years.

但是，像come,arrive,buy等终止性动词不能与表示“一段时间”的状语连用。要用，必须改为“be(在)”等延续性动词来表述。

现归纳总结一下由非延续性动词到延续性动词的转换：

　　arrive→be here begin(start)→be on

　　die →be dead come back→be back

　　leave →be away from ill(sick,asleep)→be ill(sick,asleep)

　　get up→be up go out →be out

　　finish →be over put on →wear 或be on

　　open →be open join →be in或 be a member of…

　　close →be closed go to school→be a student

　　borrow →keep buy →have

　　catch(a cold)→ have(a cold) get to know →know

　　begin to study→study come to work→work等

如：He has been a soldier for three years.他参军三年了。

　　His father has been dead for two years.他父亲去世二年了。

　　The film has been on for ten minutes.电影已开始十分钟了。

　　We have studied English for three years. 我们(开始)学英语已三年了。