1）過去時表示過去某時發(fā)生的動作或單純敘述過去的事情，強調(diào)動作；現(xiàn)在完成時為過去發(fā)生的，強調(diào)過去的事情對現(xiàn)在的影響，強調(diào)的是影響。
　
　 2）過去時常與具體的時間狀語連用，而現(xiàn)在完成時通常與模糊的時間狀語連用，或無時間狀語。

一般過去時的時間狀語:
yesterday, last week，…ago, in1980, in october, just now, 具體的時間狀語

共同的時間狀語:　
this morning, tonight,this april, now, once，before, already, recently，lately　

現(xiàn)在完成時的時間狀語
for, since, so far, ever, never, just, yet,　　　　　　till / until, up to now, in past years, always,
不確定的時間狀語
　
　 3）現(xiàn)在完成時可表示持續(xù)到現(xiàn)在的動作或狀態(tài)，動詞一般是延續(xù)性的，如live, teach, learn, work, study, know.
　 過去時常用的非持續(xù)性動詞有come, go, leave, start, die, finish, become, get married等。
　舉例：
　 i saw this film yesterday.
　�。◤娬{(diào)看的動作發(fā)生過了。）
　 i have seen this film.
　�。◤娬{(diào)對現(xiàn)在的影響，電影的內(nèi)容已經(jīng)知道了。）　
　 why did you get up so early?
　�。◤娬{(diào)起床的動作已發(fā)生過了。）
　 who hasn't handed in his paper?　
　�。◤娬{(diào)有卷子，可能為不公平競爭。）
　 she has returned from paris.　
　　 她已從巴黎回來了。
　 she returned yesterday.
　　 她是昨天回來了。
　 he has been in the league for three years.
　　(在團內(nèi)的狀態(tài)可延續(xù))
　 he has been a league member for three years.
　　(是團員的狀態(tài)可持續(xù))
　 he joined the league three years ago.　
　　( 三年前入團，joined為短暫行為。)
　 i have finished my homework now.　
　
　 ---will somebody go and get dr. white?
　 ---he's already been sent for.　
　 句子中如有過去時的時間副詞（如 yesterday, last, week, in 1960）時，不能使用現(xiàn)在完成時，要用過去時。
　 （錯）tom has written a letter to his parents last night.
　 （對）tom wrote a letter to his parents last night.