八年级英语下册第三单元的知识点有哪些?

八年级英语下册第三单元的知识点有哪些?
八年级英语下册第三单元的知识点有哪些?

八年级英语下册第三单元的知识点有哪些?
Unit 3      What were you doing when the UFO arrived?

【单元目标】
1．单词与短语
well, buy, cut, land, while, experience, strange, around, follow, climb, shout, run, anywhere, happen, accident, modern, bright, silence, destroy, meaning, souvenir
1.get out (of) 2.in front of / in the front of 3. take off
4.buy for 5. land on 6. shout to / at 7.run away
8.come in 9.hear about  10.the Museum of Flight 
11.happen to 12.stop doing 13.take place 14.as... as

2．目标句型：
1. What were you doing when...? 2. I was doing sth. when...
3. How about... / What about...? 4. What happened next?
5. While sth./sb. was doing sth., I did...
3．语法
1. 过去进行时
2. 情态动词的用法Ⅱ
【重难点分析】
一. 过去进行时
过去进行时表示过去某一时刻或者某段时间正在进行或发生的动作,常和表过去的时间状语连用,如：
    I was doing my homework at this time yesterday.昨天的这个时候我正在做作业.
    They were waiting for you yesterday.他们昨天一直在等你.
        过去进行时的构成：
肯定形式：主语+was/were+V-ing
否定形式：主语+was not (wasn't)/were not (weren't)+V-ing
疑问形式：Was/Were+主语+V-ing.

基本用法：
1.过去进行时表示过去某一段时间或某一时刻正在进行的动作.常与之连用的时间状语有,at that time/moment, (at) this time yesterday (last night/Sunday/week…), at+点钟+yesterday (last night / Sunday…),when sb. did sth等时间状语从句,如：
    What were you doing at 7p.m. yesterday? 昨天晚上七点你在干什么?
    I first met Mary three years ago. She was working at a radio shop at the time. 我第一次遇到玛丽是在三年前,当时她在一家无线电商店工作.
    I was cooking when she knocked at the door. 她敲门时我正在做饭.
        2. when后通常用表示暂短性动词,while后通常用表示持续性动词,因此它所引导的状语从句中,谓语动词常用进行时态,如：
    When the car exploded I was walking past it.= While I was walking past the car it exploded.
        3.when用作并列连词时,主句常用进行时态,从句则用一般过去时,表示主句动作发生的过程中,另一个意想不到的动作发生了.如：
    I was walking in the street when someone called me. 我正在街上走时突然有人喊我.
        4. when作并列连词,表示“（这时）突然”之意时,第一个并列分句用过去进行时,when引导的并列分句用一般过去时.如：
    I was taking a walk when I met him. 我正在散步,突然遇见了他.
    We were playing outside when it began to rain. 我们正在外边玩,这时下起雨来了.
二. 情态动词(Modal Verbs )Ⅱ

4、情态动词表示“应该”、“必须” （shall, should, may, might, must, ought to）
（1）shall 和 should 用于表示“必须”：
①. Each member shall wear a name card. (表示规定) 每一个会员必须配带名卡.
②. I should answer his letter as soon as possible. (表示应该) 我应该尽快给他回信.
③. You shouldn't judge a man always by the clothes. (shouldn't “不应该”含有劝告的意思)
你不应该总是以貌取人.
④. The rules shall take effect on Jan. 1st. (shall 用于规章等,表示义务和规定)
新规则于一月一日起生效.
（2）may 和 might 用于表示“应该"(多用于法律等条文,一般上多用 shall):
①. Payment may be paid by check.(表示规定) 应以支票付款.
②. You might ask before you use my computer. (might表示应该)
你应该先问过再使用我的电脑.
（3）must 用于表示“必须”、“务必”：
①. You must keep the place clean. (务必) 你务必保持地方干净.
②. We must obey orders. (表示有义务) 我们必须服从命令.
③. Must I pay now? (用于疑问句) (如回答不必时,需用 needn't 或 don't have to)
我现在就得付款吗?
5、情态动词表示“意图”、“打算”
(will, would, shall, should)
（1）will 和 would 用于表示某种意图：
①. I'll call you as soon as possible. (will 主要用于第一人称) 我会尽快打电话给你.
②. Will you accept this invitation? (用would 则表示更客气) 你愿意接受这邀请吗?
③. Who will do the job? (用于条件句,可用于各种人称) 谁愿意做这事?
④. We won't (will not) stay here too long. (will not 表示不愿) 我们不愿呆在这里太久.
（2）shall 和 should 用于表示说话人的意图：
  ①. We shan't (shall not) go if it rains. (shall not 也可用 will not)
如果下雨,我们就不打算走了.
②. I shan't go with you. (shall 只用在第一人称) 我不打算和你一同走.
6、情态动词表示“意愿”
（will, would, shall, should）
（1）will 和 would ：
①. She will do it if you ask her.(表示主语的意愿) 如果你问她,她会做的.
②. Would you have another cup of tea? (用 would 比 will 客气) 你想再来一杯茶吗?
③. Will you have some cookies? (will用于疑问句,表示问人是否愿意)你想吃些烤饼吗?
④. If he will, he can do it. (will 用于条件句,用于第二、三人称) 如果他愿意,他会做的.
⑤. Would you excuse me? (would 表示婉转语气) 你能原谅我吗?
（2）shall 和 should ：
①. He shall get his allowance. (注意是he shall, 表示说话人的意愿)他会拿到他的津贴的.
②. You should sit here as long as you like. 只要你乐意,坐多久能行.
③. Shall you go to school with me? (疑问句中,表示问对方的意愿)
你愿意和我一起到学校去吗?
三. 重点词汇
1．cut v．切；剪；割
cut (one’s)hair   理发
Be careful．Don't cut yourself．小心,别切到自己.

2．alien n．外星人
Nobody knows whether there are aliens or not．没人知道到底有没有外星人.
An alien got out of the UFO.  一个外星人从不明飞行物里出来.

3．land v．登岸；登陆；降落
The plane will land in ten minutes．飞机将在十分钟后降落.
A UFO landed in the middle of the field..  一个不明飞行物降落在田野中间.

4．while conj．当……的时候；在……之时
While I danced, she sang．我跳舞,她唱歌.
While he was singing, I was playing baseball.  他当时在唱歌,而我在打棒球.

5．right adv．正好；恰好
The accident happened right over there．事故正好发生在那里.
He lives right in the center of the city.  他恰好住在市中心.

6．surprised adj．惊奇的；吃惊的
I was surprised that he was late for the party．我很惊讶他聚会居然迟到了.
She was surprised that I didn’t know about that.  她很吃惊我竟不知那件事.

7．kid v．欺骗；哄骗
I'm not kidding you．我没有骗你.
You’re kidding = No kidding.   别开玩笑了.

8．anywhere adv．到处；无论哪里（用于否定句和一般疑问句中）
Did you go anywhere yesterday? 你昨天去没去过什么地方?
They didn’t go anywhere the day before yesterday. 他们前日天哪里也没去

9．happen v．发生
A funny thing happened in the subway yesterday． 昨天地铁里发生了一件有趣的事. 
What happened to him on that day?  那天他怎么了?（发生了什么事?）
sth. happen to +名词 发生于……身上
She hoped nothing bad would happen to him．她希望不会有坏事发生在他身上.

10．get out of 从……出去
She tried to get out of helping her mother．她尽量逃避帮助她的妈妈.
Tom got out of the lift and walked to the station.  汤姆走出电梯然后往车站走去.

11．run away 跑开；迅速离开；逃走
The thief ran away when someone noticed him．当有人注意到他的时候,那个贼立刻逃走了.

12．at the doctor's 在诊所；在医院 
I'm thinking of going to the tailor's．在表示诊所、店铺或某人的家时,经常用名词所有格的形式.
Mr. Cool’s = Mr. Cool’s clothes store at Jason’s = at Jason’s store
She is staying at Mary's．她住在玛莉家.
I want to go to the tailor’s.  我想到裁缝店去一趟.

13. see sb. Do sth. 看见某人做(过)某事
she saw the alien get out.  她看见外星人出来.

四．词语辨析
1、in front of 与in(at) the front of
in the front of  在……的前面 （表示“有距离的前面”,在一个参照物的前面）
e.g.: There is a car in front of the house.  房子前日面有一辆车
in(at) the front of  在……的前头,前排（列）（在一个范围内的前面部位）
eg. She sat in the front of the bus.  她坐在公交车的前排
 
2、get out of 与get into 是反义词
get into走进,进入
eg. He get out of the car and get into the building.
 
3、be amazing与be amazed
be amazing 令人惊奇的（修饰事物的,指某事令人惊奇,比surprising更具意外性
e.g.:She has an amazing talent for music.她在音乐方面有惊人的才华.
Isn’t that amazing .那不很令人意外吗?
 be amazed (at sth./to do …/that 从句)（某人）对…(因…而)大感惊讶(指人作主语)
eg. We were amazed at the news.=We were amazed to hear the news.
我们对这个消息感到非常惊讶.
 
4、be surprising与 be surprised
be surprising令人惊奇的（用法与be amazing一样,也是修饰事物的）
e.g.:a surprising ending 一个令人惊奇的结局
be surprised (at sth./to do…/that从句) （某人）对…(因…而)感到惊奇,用法与be surprised
一样,也是人作主语.
eg. They were surprising that he was badly hurt in the audient. 他们很吃惊他在那次事故中伤得很重.
 
5、in a tree与 on a tree
eg. Are there any birds in the tree?  树上有些鸟吗?
on a tree 在树上（指长在树上的东西）
Look! There are many apples on the tree.
 
6、my flight to New York 与 fly to New York
前者是一个名词短语,后者是一个动词短语.
eg. Her flight to Paris is taking off at 2 p.m.
She is flying to Paris at 2 p.m.
 
五.课文解释：
1. You can imagine how strange it was!你可以想象这事有多惊奇!
eg. You can imagine how fast he runs!
 
2. I followed it to see where it was going
    follow sb. to do sth. 跟随…去做…
eg. Mr White followed his wife to see what was happening there.
 
3. She didn’t think about looking outside the station.
Think about (doing) sth. 她未想到去车站外看看.
 
4. say to sb.  对某人     say to oneself  自言自语
e.g.: He said to himself, “Don’t be afraid.” 他自言自语,“不要害怕”
 
5. look for  寻找（强调找的“过程”） find 找到（强调找的“结果”）
eg. He looked for his lost key everywhere but couldn’t find it.
 
6. It was difficult to get out of bed.  从床爬起来很难.
It is difficult/hard to do sth.  做某事很难.
He found that it was difficult to learn physics well.
 
7. be killed  被杀害  be destroyed by…  被……摧毁……

8. walk home together in silence  沉默着一起走回家
in silence  状语（状态）
   
9. Not all events in history are as terrible as this.
并不是所有的历史上的大事件都像此事这样可怕.
Not all  并不是所有的（部分否定）
As…as…  与……一样(as与as之间用形容词、副词的原级)
 
10. become the first Chinese astronaut in space. 成为中国首位进入太空的宇航员
 
11. His flight around the Earth Lasted about 22 hours. 他的环绕地球的飞行持续了22个小时.
 
12. Do you think sth. good can come out of sth. terrible? 你认为坏事能变为好事吗?