1 现在完成时讲解
1 构成方式 构成： 主语（第一、二人称单复数）＋have
主语（第三人称复数）＋have
主语（第三人称单数）＋has ＋过去分词
2 基本用法
1) 表示过去发生或已完成的某个动作对现在产生的影响或结果,强调的是这个影响或结果,常同already, just, yet等状语连用
例：I have just turned off the light. 我刚刚把灯关上.（结果是灯已经关上了）
She has lost her bike. 她把自行车丢了.（影响是他现在没有自行车骑了）
The rain has stopped now. 雨已经停了.（结果是我们可以出门了）
I have already read the book. 我已读过这本书了.（结果是已知道这本书的内容）
She has had a good education. 她受到过良好的教育.（影响是她文化水平高,有修养）
2) 表示开始于过去、持续到现在的动作或状态,并可能继续下去（也可能不继续下去）,常同包括现在在内的时间状语连用,如：today, now, this week, this morning, these days, this afternoon, recently, so far等；也同“for+时间段”或 “since＋时间点”的状语连用
例：We have had much snow this winter. 今年冬天多雪.
She has taught in the school for ten years. 她在这所学校教书已经10年了.
I haven't eaten anything since breakfast. 我从早饭起就一直没有吃东西.
We have been busy this morning. 今天上午我们一直很忙.
I have known her since we were children. 我从小就认识她.
I haven't seen John today. 我今天没有见到约翰.
It has rained a lot these days. 这些天多雨.
3) 表示从过去某一时间到说话时这段时间中反复发生的动作或多次动作的总和,常同频度副词always, often, seldom, never等连用
例：He has done a lot of work in the past two years. 在过去两年中他做了许多工作.
I have learned about two hundred English words this morning. 本月我学了大约200个英语单词.
I have been to the Great Wall twice. 我曾经去过长城两次
It has rained every day this week. 这个星期天天下雨.
She has always walked to school. 她一直步行去学校.
I have never seen such a beautiful bird. 我从没见过这么美丽的鸟.
I have often met the old man on my way to work. 我在上班的路上常常遇见那位老人.
4) 现在完成时与一般过去时的区别
1．现在完成时强调过去发生的动作对现在的影响和结果,而一般过去时与现在没有联系,只是说明某个动作发生的时间是在过去.
比：I have washed the car. 我洗过了车.（看上去很漂亮）
I washed the car a moment ago. 我刚才洗过车了.
She has watered the flowers. 她已经浇了花.（不需要再浇了）
She watered the flowers yesterday. 她昨天浇的花.
I have written the letter but I haven't posted it yet. 信我已经写好了,但还没有寄出.
I wrote the letter last week and I posted it three days ago. 我上周写的那封信,3天前寄出的.
2．现在完成时表示的动作或状态延续到现在并可能延续下去,而一般过去时则单纯表示过去某段时间内的经历.
比：It has rained for five hours. 雨已经下了5个小时了.
It rained for live hours yesterday. 昨天下了5个小时的雨.
He has waited for her for two hours. 他等她已经两个小时了.
He waited for her two hours and then went home. 他等她等了两个小时,然后就回家了.
I have reviewed two lessons this morning. 今天上午我已经复习了两课.（说话时还在上午）
I reviewed two lessons this morning. 今天上午我复习了两课.（说话
3 现在完成时讲解
Clark became a driver two years ago. 克拉克两年前当了驾驶员.
The meeting has been on for five minutes. 会议已经开始5分钟了.
The meeting began five minutes ago. 会议5分钟前开始的.
Daisy has been up for ten minutes. 戴西起床已经10分钟了.
Daisy got up ten minutes ago. 戴西10分钟前起的床.
如果非延续性动词用于现在完成时的否定式,则可同一段时间状语连用,并可同“for＋一段时间”或“since＋一时间点”和“since＋句子”连用.
例：She hasn't left home for a year. 她离开家还不到一年.
I haven't seen Jamie for two months. 我两个月没见杰米了.
The old man hasn't returned to his hometown for about fifty years. 这位老人约有50年没有回家乡了.
I haven't met her since I left school. 我毕业以来没有见到她.
We haven't heard from Kent since 2001. 自2001年以来我们都没有收到肯特的信.
非延续性动词的否定式与till(/until)结构从句连用,表示“直到……才”,指某个不发生的动作一直延续到某个时间点才结束.
延续性动词的肯定式与till(/until)结构连用,表示该动作一直延续到某个时间点才结束
比：I didn't finish the experiment until midnight. 我直到半夜才做完实验.
I watched TV until midnight. 我看电视一直到半夜.
The flower show didn't begin till the foreign friends arrived. 花展直到外国朋友们到才开始.
He worked in the office till the foreign friends arrived. 他在办公室一直工作到外国朋友到达.
They didn't set out until the moon rose. 他们直到月亮升起了才动身.
They waited until the moon rose. 他们一直等到月亮升起.
7) It has been(/is) ＋一段时间＋since从句
这种句型表示“自从……”,since从句通常用一般过去时.
例：It has been ten years since he came to the city. 他来这座城市已经10年了.
It is about 5 days since she fell ill. 她生病大约5天了.
It is three months since Louis lost his car. 路易斯丢车已有3个月了.
8) have (has) got的用法
have(has) got形式上是现在完成时,实际上意思与have (has)相同.have(has)got 是英国英语,have (has)是美国英语.
例：I have got (have) a bad cold. 我得了重感冒.
Have you got a rubber? 你有橡皮吗? =Do you have a rubber?
