英语动词时态:现在完成时

现在完成时是英语时态中最不好掌握的时态,因为对我们来说,它很难在汉语中找到相对应的说法,下面笔者从几个方面分析一下现在完成时的用法.
1． 现在完成时的定义：
2． 强调过去的动作和状态对现在产生的影响和结果.
常用的时间状语有：already,yet,never,有时没有时间状语；多是一般疑问句.
I have already seen the film.
Have you decided yet?
3． 刚刚和最近发生的动作和状态.
常用的时间状语有：just,lately,recently,in the past few days/weeks
注意：just 和just now用不同的时态,just now(刚才)一般用过去时.
I have just phoned him?
I have visited my parents recently.
4． 从过去一直延续到现在的动作和状态.
常用的时间状语有：since,（可用作介词和连词）for
注意：主句的谓语动词一般是延续性的动词,如果是否定形式,主句的谓语动词可用瞬间动词,否则,不能用瞬间动词.
I have lived here for 20 years.
I have lived here since I came to this city
I have learned English since 10 years ago.
He hasn't come to visit us for a few months.
5． 从过去到现在一段时间的动作和状态.
常用的时间状语有：up till now,so far,in this morning,in this week,in this year,in my life
注意：这两句话的区别
I have seen him this morning.(时间还在上午)
I saw him this morning.(时间不是在上午了)
We have learned so many things from you so far.
I have seen any bird like this in my life.
6． 对过去的体验和经历.
常用的时间状语有：before,ever,once,twice,many times
注意：这两句话的区别
I have been to Beijing （去过北京）
I have gone to Beijing（去北京了,人还没回来〕