一般过去时现在完成时所表示的动作都发生在过去,那么这两种时态有什么区别呢?
一般过去时与具体的表示过去时间状语如:yesterday连用;强调动作在过去发生,与现在无关.
现在完成时与自已的特征词连用,强调过去发生的动作对现在的影响或过去开始发生一直持续到现在的动作.
例:He saw the film last night. (过去时,表示他昨晚看过那部电影了,现在不知还要不要再看一次)
      He has (ever) seen the film before.(现在\完成时,表时他已看过那部电影,现在不想再看了)
  用于现在完成时的句型
1)It is the first / second time…. that…结构中的从句部分,用现在完成时.
   It is the first time that I have visited the city.
   It was the third time that the boy had been late.
2)This is the… that…结构,that 从句要用现在完成时.
   This is the best film that I've (ever) seen.这是我看过的最好的电影.
   This is the first time (that) I've heard him sing. 这是我第一次听他唱歌.
1.现在完成时不能单独与准确时间状语连用,(如表示过去的时间状语)如yesterday(morning、afternoon),last(morning、afternoon)等,除非与for,since连用.
2.现在完成时往往同表示不确定的过去时间状语连用如already(肯定句中),yet(否定,疑问,句末),just,before,recently,still,lately,never等
   He has already obtained a scholarship.他已经获得了一份奖学金。
   I haven't seen much of him recently (lately).我已经很久没有看到他(最近的)。