八年级下册英语Unit3语法解析
对于初二学生来说，语法是学习英语过程中的一个重要模块，接下来学习啦小编为你整理了八年级下册英语Unit3语法解析，一起来看看吧。
八年级下册英语Unit3语法过去进行时概念讲解
以上四句是由when与while引导的时间状语从句。这四句中还包含了一个很重要的时态：过去进行时。
1. 构成：过去进行时由 “was / were +动词-ing”构成
2. 意义：
(1) 表示在过去某一时刻或某一段时间正在进行的动作。这一特定的过去时间除有上下文暗示以外，一般用时间状语来表示。如：
— What was he doing when the UFO arrived? 当UFO落地时他正在干什么?
— He was sleeping late when it arrived. 当UFO落地时她正在熟睡。
Many people remember what they were doing on April 4, 1968.
许多人记得在1968年4月4日他们正在做什么。
(2) 表示过去某一动作发生时另一动作正在进行。一个长动作发生的时候，另一个短动作也发生。
3. 标志词：
(1) at 9 o'clock yesterday, from 8 to 9 yesterday morning, at this / that time yesterday, this morning, the whole morning, all day yesterday, when, while, 如：
We were having an English class at 9 o'clock yesterday.
昨天9点我们正在上英语课。
Xiao Ming was sleeping all day yesterday.
昨天一整天小明都在睡觉。
(2) 主句(过去进行时)+ when + 从句(一般过去时)
(3) 主句(一般过去时)+ while +从句(过去进行时)
The girl was shopping when her friend saw her.
当她的朋友看见她时女孩在买东西。
The dog got out of the box and ran away while Linda was buying the newspaper at the station.
当Linda 在车站外买报纸时，狗从箱子里出来逃跑了。
4. 过去进行时的各种句式：
下面以动词work 为例，将过去进行时的肯定式、否定式和疑问式以及简略答语归纳如下：
肯定式：I / He / She / It was working.
We / You / They were working.
否定式：I / He / She / It was not working.
We / You / They were not working.
疑问式和简略回答：
— Was I working? — Yes, you were. / No, you were not.
— Were you working? — Yes, I was. / No, I was not.
— Was he / she / it working? — Yes, he / she / it was. / No, he / she / it was not.
— Were you / they working? — Yes, you / we / they were. / No, you / we / they were not.
注：was not常缩略为wasn't; were not常缩略为weren't.
5. 比较：
(1) 一般过去时与过去进行时用法比较：
■一般过去时表示在过去某个时间发生过的动作或存在的状态，而过去进行时则表示在过去某一时刻或某一时间正在进行的动作。如：
David wrote a letter to his friend last night.
大卫昨晚给他的朋友写了信。(信写完了)
David was writing a letter to his friend at 8 last night.
昨晚8点大卫一直在给他的朋友写信。(信不一定写完)
■表示过去将来，多用于go, come, leave, start, take off等动词。如：
He said he was leaving for home in a day or two.
他说他一两天之内就动身回家了。
■表示过去的经常动作，常与always, forever等连用，略带感情色彩。如：
She was always thinking of others. 她老是想到别人。(赞扬)
She was forever complaining. 她老是抱怨。(厌烦)
(2)when 与while区别
■when表示“当……的时候”。从句中既可用延续性动词，又可用非延续性动词，这些动词既可以表示动作，又可表示状态，常跟一般过去时。
When the UFO took off, the boy was taking photos.
当 UFO起飞时，男孩在照相。
Mary was having dinner when I saw her.
当我看见她时玛丽吃午饭。
The boy was still sleeping when his mother got home yesterday morning.
昨天早上当她的母亲到家时男孩仍然在睡觉。
■While表示“在……的时候”“在……期间”。while从句中必须是表示动作或状态的延续性动词，常跟过去进行时。
While the boy was taking photos, the UFO took off.
当男孩在照相时, UFO起飞了。
The weather was fine while we were in Beijing.
当我们在北京时天气很好。
注：如果主句的动作在从句的动作过程中发生，从句常用进行时。
While we were swimming someone stole our clothes.
当我们在洗澡时有人偷了我们的衣服。
Don't talk so loud while others are working.
当其他人在工作时不要大声喊叫。
■表示两个同时持续的动作。
I was doing my homework while he was listening to music.
我在做作业而他在听音乐。
注：通常不能用于过去进行时的动词主要有：agree, is, am, are, believe, belong, care, forget, hate, have (拥有), hear, know, like, love, mean, mind, notice, own, remember, seem, suppose, understand, want, wish等。
八年级下册英语Unit3语法常见题型
Ⅰ. 句型转换
(1) We were listening to the teacher when she came in. (对划线部分提问)
_____ _____ you _____ when she came in?
(2) He does his homework every day. (用at this time yesterday改写句子)
He ____ _____ his homework at this time yesterday.
以上(1)小题是对过去进行时句式改变的练习，只需照以上讲解完成即可。(2)小题考察一般过去时与过去进行时的熟练转换。
Ⅱ. 用“when”与“while”完成句子。
(1) _____ Tom was eating supper, it began to rain outside.
(2) Don't use your cell phone _____ you are driving a car.
(3) What were you doing _____ Mr. Zhou came in?
(4) Jim is good at math _____ Mary is good at English.
(5) We were watching TV_____ the electricity was off.
对于以上题目，同学们只要掌握“when”与“while”引导的时间状语从句主从句所用的时态就可以了。对于其他的用法我们将到九年级去学。
Ⅲ. 单项选择
(1) I first met Lisa three years ago. She ___ at a radio shop at the time.
A. has worked B. was working
C. had been working D. had worked
(2) My mother was reading while I ___ the music.
A. listened to B. listened C. was listening to D. is listening to
(3) I ___ my breakfast when the morning post came.
A. had B. had been having
C. have been having D. was having
(4) When I arrived at his office, he ___ on the phone.
A. was speaking B. spoke
C. had been speaking D. had spoken
在以上题目中，(1)题考察在过去某一时刻发生的动作，即用过去进行时。(2)题考察while引导的时间状语从句两个动作同时发生，都用过去进行时。(3)(4)题考察when引导的时间状语从句，主句用过去进行时，从句用一般过去式。其他无须多考虑，从句，主句用过去进行时。
Ⅳ. 汉译英
(1) Lucy 和Lily昨天下午从3点到4点在游泳。
Lucy and Lily ______ ________ from 3:00 to 4:00 yesterday afternoon.
(2) 当Mr Cook到家时，他正在听收音机。
When Mr Cook got home, his son ______ ______ to the radio
(3) 当李雷在吃早饭时，吉姆进来了。
While Li Lei ______ ______________, Jim came in.
八年级下册英语Unit3常见题型答案
句型转换：
(1)What were; doing (2)was doing
用“when”与“while”完成句子：
(1) while (2) while (3) when (4) while (5) when
单项选择：
(1) B (2) C (3) D (4) A
汉译英：
(1) were swimming (2) was listening (3) was having breakfast
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