一.核心语法
【知识梳理】
1感悟生命作文.现在完成时
【拓展】
1)表示过去的动作对现在造成的影响或结果，着眼点在现在，常与already, yet, just ,before, lately, recently, never, ever, not yet等连用。这个动作到说话时可能已经停止或结束。
He has turned off the light. 他已把灯关了。
His brother has joined the Party already.   
I have finished reading the book.
We have just visited the farm.   
2)表示动作或状态在过去某时开始，一直持续到现在，并还可能继续下去的动作或状态。通常用延续性动词。常与段时间状语连用。如：so far, up to now, since, for+一段时间，in/over /during the past/last few years等。
He has lived here since 1995. 自从1995年以来，他一直住在这儿。
I have not seen Justin since last Friday night. （从上周五晚上到现在一直都没有见过Justin）
I have taught English for 15 years.
Up to now, we have received no news from her.
批注：现在完成时还可和包括 “现在”在内的时间状语连用，如：today, this morning, this month, these days, this year等,表示这个动作在这个特定的时间内完成.
Have you seen her these days?
但如果说话人感兴趣的只是在这段时间内发生了某一动作，而不是这一动作与现在的关系时，须用过去时态。
The conference opened this month.
3)在时间、条件、让步状语从句中，用现在完成时表示将来完成的动作。（即用现在完成时代替将来完成时）。
其特征为：状语从句中的谓语动词很明显或需强调发生在主句谓语动作之前。
They will go to work in the company as soon as they have graduated from the school. (强调毕业后)
扫除力I will not believe you unless I have seen it with my own eyes. （强调先看到）
I will go with you as soon as I have finished my work. （强调“干完”）
Tell me your answer when you have solved the problem! （强调“解决”）
4)使用现在完成时的句型 
亡羊补牢的道理① It /This is the first / second time…that…结构中的从句部分，用现在完成时。
It is the second time that I have visited the city.
This is the first time (that)I’ve heard him sing.
注意：It was the third time that the boy had been late.
童蒙养正② This is +形容词最高级+名词+that…结构，that 从句要用现在完成时。
This is the best film that I’ve (ever)seen.
This is the only book that he has written.
5）固定句型
It is/has been +时段+since+从句（从句谓语为瞬间——则按字面翻译）
                              （从句谓语为延续——则表示未做此事多久）
如：It is/has been two years since we arrived here. 我们到这儿两年了。
      It is two years since he lived here. 他不在这儿住两年了。
【典例讲解】
例1：—I remember you were a talented pianist at college. Can you play the piano for me?
—Sorry, I ______ the piano for years.
A. don't play      B. wasn't playing      C. haven't played        D. hadn't played
答案：C
解析：根据remember可知语境是现在，从时间状语for years 得出是从过去到现在的时间，所以用现在完成时。
2.现在完成进行时
【拓展】
表示一个持续到现在的动作(这动作可能刚停止，也可能还在进行)。
(1) 构成：have been doing
(2) 用法：
1) 延续：表示开始于过去的活动持续到现在，并且活动往往还没有结束，将继续持续下去。
I have not been sleeping well since I returned home.( “我”回家后一直都没睡好，现在也没睡好。)
I have been living in Hawaii for ten years.我在夏威夷已经生活了十年。
She has been burning the midnight oil to prepare for GRE.她最近在熬夜准备GRE考试。
Tom has been playing the online games for more than twenty hours.汤姆玩网游已经超过二十个小时了。
2) 重复：到目前为止的一段时间内重复发生的活动。
He has been going to Seattle for half a year.他在半年间经常去西雅图。
I have been telling you not to make trouble.我一直劝你不要麻烦。
The old man has been repairing cars for thirty years.老人修车修了三十年了。
Jack has been practising Tai Chi for more than a year.杰克练太极一年多了。
3)表示感情彩
现在完成进行时比较生动，有时含有明显的感情彩。
如：What have you been doing? 表示惊异
  Who's been eating my apples? 表示愤怒不满
【典例讲解】
例1：Tom ______ in the library every night over the last three months.
学习硬笔书法A. works                  B. worked                   
C. has been working          D. had been working
答案：C
解析：over the last three months 的意思是“在过去的三个月期间”，这类时间状语通常与现在完成时或现在完成进行时连用，四个选项中只有C符合此要求。
例2：Now that she is out of a job, Lucy ______ going back to school, but she hasn’t decided yet.
had considered              B. has been considering       
C. considered                  D. is going to consider