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 fall 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.