初二下册英语unit 1 导学案（十）,栏目：八年级英语辅导,初中英语学习方法大全 ，http://www.jiaoyu880.com 。
初二下册英语unit 1 导学案（十）
Grammar：现在完成时
现在完成时用来表示之前已发生或完成的动作或状态，但它的影响现在还存在；也可表示持续到现在的动作或状态。其构成：have (has) +过去分词。规则变化的过去分词与过去式的变化一样，在动词词尾加ed; 不规则变化的过去分词见不规则动词表，需要同学记忆。
现以see the film为例将现在完成时的肯定句，否定句和疑问句列表如下：
肯定句：I/You/We/They have seen the film.
He/She /It has seen the film.
否定句：I/You/We/They have not/ haven’t seen the film.
He/ She/It has not/hasn’t seen the film.
疑问句：Have I/you/they seen the film? Yes， you/ we/I/they have. No， you/ we/I/they haven’t.
Has he/she/it seen the film? Yes， he/ she/ it has. No， he/ she/ it hasn’t.
现在完成时中常用的一些表达：
already：已经，常用于肯定句中，放在句中或句末。用于疑问句常表示惊讶疑惑。
yet 已经，还，常用于疑问句和否定句中，放在句末。
ever 曾经，常用于疑问句中，放在句中。
never 从不，表示否定，放在句中。
just刚刚，常用于肯定句中，放在句中。
since 自从…以来，后面接时间点或从句。
for 后面接一段时间。
例：I have finished my homework already.
My cousin hasn’t returned the library book yet.
They have just given the food to the poor boy.
Have you ever spoken to a foreigner? No， never.
I have known him since ten years ago/ for ten years.
My sister has lived in Canada since she was born.
现在完成时中应注意的几个问题
1. have been to 和have gone to的区别
have been to 强调“去过”，现已不在那里，如：
He has been to the USA three times.
他到美国去过三次。（过去“到美国”，现在已“不在美国”）
have gone to主要强调的是“去了”，现在人不在说话的现场，如：
--Where‘s your mother? --你妈妈在哪？
--She has gone to the hospital. --她去医院了。
2. have been to 和have been in的区别
have been to强调人“已回到原地”，后面可接表示“次数”的状语。
eg. ①She has been to Shanghai only once.
②--How many times has he been there?
--He‘s been there many times.
have been in表示某人“已在某地停留一段时间，现仍在那里”，其后常带表示一段时间的状语。
eg. ①They have been at the bus stop for half an hour.他们在车站呆了半小时。（现在仍然在车站）
②We have been in Xi‘an for two weeks.
我们在西安呆了两个多星期。（现仍在西安）
③How long have they been in China?
他们在中国呆了多长时间了？（仍在中国）
3. 现在完成时与一般过去时的区别
现在完成时表示过去发生的某一动作对现在造成的影响和结果，强调的是现在的情况，所以它不能和表示过去的时间状语连用。而一般过去时只表示过去的动作或状态，和现在不发生关系，它可以和表示过去的时间状语连用。
eg. I have done my home work. 我做完作业了。
I did my homework yesterday evening.
我昨天晚上做了作业。（只说明昨天做了，而不涉及现在情况）
4. 瞬间动词在现在完成时中的使用
A. 瞬间动词可以用于现在完成时，如：
He has fallen asleep.他已入睡。
B. 瞬间动词原则上不能和表示一段时间的状语连用，但在否定句中可以使用。如：
She hasn‘t had a letter yet.她仍然没收到信。
She has bought the car for a year.
上句应改为：She has had the car for a year.
或It is one year since she bought the car.这辆车她买了一年了。
常见的瞬间动词有：come， arrive， get to， get up， reach， leave， go， die， become， open， finish， join， buy， borrow， lend ， begin， start等。
如果句中有表示一段时间的状语，需将瞬间动词改为延续性动词，现归类如下：
borrow- keep buy- have die- be dead come/ go/ arrive - be in leave- be away from open- be open begin- be on get up- be up join- be in/ be a member of
ag: The film has begun. It has been on for half an hour.
The factory opened three years ago.= The factory has been open for three years.
Tom has left home. he has been away from home for two hours.
>>点击查看更多有关初一下册英语unit 2 will people have robots?的学习资料
www.jiaoyu880.com【典型例题】
1. — Oh， Mrs. King， your necklace looks nice. Is it new?
—No， I ____ it for two years.
A. had B. have had C. bought D. have bought
2. His grandfather _____ for over two years.
A. has died B. has been dead C. has dead D. died
3.Uncle Li can speak English very well because he _____ England for 5 years.
A. has gone to B. has been to C. has come to D. has been in
4. — Where is Mr. Zhang? —He _____ London.
A. has been to B. has been C. has gone D. has gone to
5. — _____ to the United States? —No， never， but I went to Canada a few years ago.
