现在完成时表示过去的动作或状态持续到现在并且已经完成,对现在造成的影响,可能持续发生下去。可以与现在完成时的时间副词或表达式有 just,already,yet,for …,since …,ever,never 和 before .
一、just 指最近发生的事件,只放在动词(过去分词)之前,例如:
No, I’ve just had dinner.No, I’m afraid he’s just gone out.二、already 指在现在之前的某个时间发生的动作,表明没有必要重复,它的位置比较灵活,可以放在动词(过去分词)之前或句末,例如:What time does the film start?动词之前:It has already started.句末:It has started already.三、yet 指迄今为止发生的事件,用于否定句和疑问句中并置于句末,例如:Have you eaten the apples yet?
四、for 用于讨论一个时间段,这个时间段不一定是确定的,但必须是一段时间,例如:He has lived in Paris for a long time.The company has been in business for four years.I have lived here since 2010.I haven't seen you since the wedding.I have been walking since 5 p.m.六、ever/never 表示现在之前一个不确定的时间,只放在动词(过去分词)之前,例如:He has never been abroad.Have you ever been to Europe?七、before 用于将早期的事情与讲话的时刻(截止讲话的时间)联系起来,例如:I have been there before.I’m so looking forward to the trip. I haven’t been to Latin America before.