一般过去时与现在完成时的区别

1）一般过去时表示过去某时发生的动作或单纯叙述过去的事情，强调动作；现在完成时为过去发生的，强调过去的事情对现在的影响，强调的是影响。 

2）一般过去时常与具体的时间状语连用，而现在完成时通常与模糊的时间状语连用，或无时间状语。 

一般过去时的时间状语：yesterday, last week，…ago, in1980, in October, just now等，皆为具体的时间状语。 
现在完成时的时间状语：for, since, so far, ever, never, just, yet, till/until, up to now, in past years, always等，皆不确定的时间状语。 
共同的时间状语：this morning, tonight, this April, now, already, recently, lately 等。 

3）现在完成时可表示持续到现在的动作或状态，动词一般是延续性的，如live, teach, learn, work, study, know.。 

4）一般过去时常用的非持续性动词有come, go, leave, start, die, finish, become, get married等
例如： 

I saw this film yesterday. （强调看的动作发生过了） 
I have seen this film. （强调对现在的影响，电影的内容已经知道了） 
Why did you get up so early? （强调起床的动作已发生过了） 
Who hasn't handed in his paper? （强调有卷子未交，疑为不公平竞争） 
He has been in the League for three years. （在团内的状态可延续） 
He has been a League member for three years. （是团员的状态可持续） 

5）句子中如有过去时的时间副词（如yesterday, last, week, in 1960）时，不能使用现在完成时，要用过去时。 

（错）Tom has written a letter to his parents last night. 
（对）Tom wrote a letter to his parents last night.