一般过去时现在完成时主要用于：1 、表示到现在为止这一时期中发生的动作或情况，即多次动作的总和。e.g. We have learnt four English songs this month.How many times have you read the novel?For many days we havent seen each other.2 、表示对现在有影响的某一已发生的动作。e.g. The delegation has left 代表团已经走了(说明现在不在这里)Look, what you have done. 看你干的事。与这一时态连用的时间状语有：already, yet, just, ever, never, by now, so far, recently, by the end of this month, since, for 短语，连词 since 引导的时间状语从句。一般过去时与现在完成时的区别：一般过去时：重在说明动作在过去发生时的具体情况(时间、地点、方式、对象、细节等)。现在完成时：只提起已发生的动作(事实)及其影响，不说明动作发生时的具体情况。cf. Have you had your lunch?What did you have for lunch?I have ever been to the Great Wall,_and_I went there last summer with my father.注：现在完成时表达的动作常具有反复性，故下面一句是错的：Have you seen the six thirtys news program?应改为：Did you see the six thirtys news program?