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1、第二单元知识点总结Unit 2： Grammar Summary （一般过去时，过去进行时，现在完成时）1. 一般过去时1) 构成： 主语+ 动词过去式 （V+ed 或特殊变化） He attended the wedding last Sunday. He didnt attend the wedding last Sunday. Did he attend the wedding last Sunday? (Yes, he did. / No, he didnt) 2) 常见时间状语： last week / year / summer 3 years ago / 2 hours ago
2、in 1998 / in May, 1998 / on Feb. 23rd 3) 使用：A. 过去大背景下，表达习惯，状态等。比如： - When he was young, he had many friends and he liked hanging out with them. They often went to the lake for summer vacation. (可用于写人物传记：) - When my grandpa was a boy, he was poor and couldnt afford to go to school at all. (表过去的状态) 我爷
3、爷是小孩子的时候，他很穷，根本上不起学。 - I went to the museum twice last year. （这个是去年的规律，有last year这个时间状语，所以用过去时） 【注意比较：He has been to the museum twice. 指到目前为止，他去过两次这个博物馆，所以用现在完成时。】 B 过去某一点时间发生的动作或事情。比如； - In 1939, the Second World War broke out. （过去某一点发生的事件）（历史书都是这么用滴）- He left two hours ago. (过去某一点发生的动作)- He droppe
4、d out of college in 1973. (传记) C表达过去一个阶段的状态。 - He worked as a journalist for 10 years. (过去一段时间内做的事情)（传记） - He was happily married for about 5 years. 他过了五年的美好婚姻生活。 D表达见面的一刻已经意识到，但是之前不知道。 - Oh, Mary, its you! I didnt know you were here in Beijing too. 2. 过去进行时 （past continuous） 1) 构成：was / were doing
5、He was watching TV at 10 oclock last night. Was he watching TV ? (Yes, he was. / No, he wasnt) He wasnt watching 2) 使用：A. 表达过去某个时间点正在做的事情，比如：- What were you doing at about 6 oclock on Wednesday? - Let me see. I was drinking in a bar with my friend Tom. (周三晚上六点正在做的事)（上面对话在警察审问时常用哦）- When he came in,
6、I was doing my homework. (时间点用从句形式表达，即他进来的时刻) B. 表达过去某段时间正在持续的动作，比如：- I was thinking about it for the whole week. (当时)我一周都在想这件事。- I was watching writing a paper on air pollution that week. 那周，我正在写一篇关于空气污染的论文。C. 过去进行时与always, never, forever 等词连用，表达感情色彩- When we were in high school, he was always comi
7、ng late to school. 当我们在高中时，他总是上学迟到。- When she was alive, she was never helping others. 她活着的时候，她从来没帮过别人。D过去进行时用于描述故事发生背景，而过去时用于表达主要动作或事件。比如：- It was raining hard that day. And I was walking in the street when suddenly I heard a loud cry coming from a store. I rushed there. (was raining, was walking 用
8、于描述故事发生背景, 而heard , rushed 用于描述主要动作)3. when, while, as 用法： 1) while 后面一般接可以持续一段时间的动作或状态，此时相当于when。 比如：- While he was doing his homework, someone knocked at the door. = When he was doing his homework, someone knocked at the door. 当他正在做作业时，有人敲门。- While I was six, I lost my father. = When I was six, I
9、lost my father. 我六岁的时候，我失去了父亲。2) when 引导的从句中，还可以是瞬间动作，即某个点时间的动作。而while是不能用在这种状况里的。比如：- When he came in, he saw a great mess in the room. (本句里，came in 是个瞬间动词, 所以此处不能用while )- When I saw him, I waved to him immediately. (本句里，saw him 也是瞬间动词) 3) 位于句中，表达“转折”，只能用while，翻译成“而”。比如： - I was cooking while he w
10、as watching TV. 我在做饭而他在看电视。 - I was only 14 years old while he was already 18 years old. 我只有14岁而他已经18岁了。- I like classical music while he likes pop music. 我喜欢古典音乐而他喜欢流行音乐。4）位于句中，翻译成“这时”，只能用when。比如： - I was having a shower when I heard someone knock at the door. 我正洗澡呢，这时，我听到有人敲门。 - I was walking in t
11、he street when I saw someone stealing a ladys purse. 我正走在街上，这时，我看到一个人偷一位女士的挎包。 - I was just about to leave home when I heard the phone ringing in the living room. 我刚要出门，这时，我听到客厅的电话响了。5） 位于句首，翻译成“随着”时，只用as, 比如: - As times passed by, things got even worse. 随着时间的流逝，事情变得更糟了。 - As children grow old, they
12、 go through many changes. 随着孩子长大，他们会经历很多变化。 - As more and more people begin to use emails, writing letters has become a rare thing. 随着越来越多的人开始使用电子邮件，写信已经成了稀有的事。6） as 如果译成“当什么时候”，所引导的从句中既可以是持续性动词，也可以是瞬间动词。 - As I was looking out of the window, I heard a crash downstairs. = While I was looking out of
13、window, = When I was looking out of window, 【注意：此时这三个连词都位于句首，后面都可以接持续性动作】 - As Yang Liwei returned into the earths atmosphere, helicopters were flying to where he would land, ready to collect him. = When Yang Liwei returned into the earths atmosphere, 【注意：此时as, when都位于句首，而且后面的returned into the earth
14、s atmosphere 是瞬间动作】4. 现在完成时1） 构成：主语 + have / has + 动词过去分词（V+ed 或特殊变化） I have seen that movie twice. I havent seen him yet. Have you seen Tom lately? 2) 常用时间状语：Since then, he has never looked back. Ive been to Hong Kong three times. I have known him for ten years. Ive already done my homework. Have you ever been abroad before? Ive seen 4 doctors so far, but no one knows whats wrong with me. He has made some progress recently / lately. I have always liked chocolate since I was a kid. People have often dreamed of traveling to out
