如：It is two years since his father died.
=His father has been dead for two years.他父亲去世已有两年了。
(3)终止性动词现在完成时的否定式，已变成一种可以延续的状态，因此可以和表示一段时间的状语连用。
如：I haven't left here since 1997.自从1997年以来，我一直没有离开过这儿。
(4) 表示行为或状态从过去一直持续到现在时，用现在完成时，要加表示一段时间的时间状语时，常用 for+一段时间, since+时间点。
I have lived here since my childhood.我从小就一直住在这里。
I have lived here for 10 years. 我在这已经住了10年了。
(5) 在提问现在完成时的时间状语时通常用 how long
How long have you lived here?
注意：在表示某一行为状态持续多长时间时，根据终止时间的不同，时态使用是不一样的。如：
I lived here for a week last summer.去年夏天我在这里住了一周。
I have lived here for a week by now. 到现在为止，我已经在这里住了一周。
I will live here for a week next year.明年我会在这里住一周。
二、现在完成时与一般过去时的区别
现在完成时用来表示之前已发生或完成的动作或状态，其结果的确和现在有联系。动作或状态发生在过去，但它的影响现在还存在;而一般过去时表示过去的事实，不表示和现在的关系。
I have just been to London. I went there last month. 我刚去过伦敦，是上个月去的。
1. 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. 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, 具体的时间状语
共同的时间状语:
this morning, tonight, this April, now, once，before, already, recently，lately
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,
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.
过去时常用的非持续性动词有come, go, leave, start, die, finish, become, get married等。
举例：
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，可能为不公平竞争。)
She has returned from Paris. 她已从巴黎回来了。
She returned yesterday. 她是昨天回来了。
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)
He joined the League three years ago. ( 三年前入团，joined为短暂行为。)
I have finished my homework now.
---Will somebody go and get Dr. White?
---He's already been sent for.
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.
三、练习题
1. A. 用 already或 yet
1) Have they taken down the old pictures ___ ___? No, they haven’t____ ___.
2) Most of us have finished our compositions _____ .
3) He said he hadn’t visited the exhibition _____ ___.
B.用 since或 for
1) We have learned five lessons __ __ _ the beginning of this term.
2) Mrs Liao has been in hospital __ _ ___last week.
3) I have stayed at my aunt’s ___ __two weeks.
C. 用have gone或 have been
1) Where are the boy students? They _____ to the school factory.
2) Is your father in? No, he ___ _ to Shenzhen. _______he ever ______ there before ?
Yes, he ___ there several times
3) He asked me if I___ __ to Hangzhou before.
I told him that I wanted to go there for a visit as I __ __ never _ ___ to that city before.
2. 选择填空
1.Mother __ __me a new coat yesterday. I _______ it on. It fits me well.
A. had made…have tried B. made…have tried
C. has made…tried D. made…tried
2 “He ____to draw horses already”. “When ______ he ?” “ Last year “
，我们将会及时处理。
