九年级上册英语Unit 4 Grammar语法讲解-译林版

Unit 4
Grammar
注意回顾学习before, after, when 和while
before和after引导的时间状语从句
Before是主句动作发生在从句的前面。

注意before引导的从句不再用否定式的谓语，并且当before引导的从句位于主句之后，有时译成“就，才”。

还要注意主句和从句之间的时间关系。

当主句用将来时，从句总是用现在时；如果before引导的从句谓语用的是过去时，则主句动词多用过去完成时，这样以便体现动作发生的先后。

After表示主句动作发生在从句动作之后。

主句和从句的动作的时间关系正好与before引导的从句相反。

例如：
It will be four days before they come back. 他们要过四天才能回来。

Einstein almost knocked me down before he saw me.
爱因斯坦几乎把我撞倒才看到我。

My father had left for Canada just before the letter arrived.
我父亲恰好在信到之前去加拿大了。

They had not been married four months before they were divorced.
他们结婚还不到四个月就离婚了。

After you think it over, please let me know what you decide.
你仔细考虑过以后，告诉我你是怎样决定的。

After we had finished the work, we went home.
完成工作之后，我们回家了。

（从句用过去完成时，主句用一般过去时）
when 的用法
如果只从现象来看，when 从句用的最多的是一般过去时，而主句的时态没有限制,根据具体情况而定。

1. When he was a child he was always trying out new ideas.
他小时候就常常试验一些新的设想。

2. When she came into my room, I was just reading a book.
她走进我房间时，我正在看书。

3. Were you writing when the teacher came in?
老师进来的时候，你在写信吗？
4. Sorry, I was out when you called me.
对不起，你打电话来的时候我出去了。

5. He was on the point of leaving when someone knocked at the door.
他正要走，这时有人敲门。

6. I thought of it just when you opened your mouth.
就在你要说话的时候，我也想到了。

7. I had hardly[scarcely] closed my eyes when someone knocked at the door.
我刚一闭上眼，就有人在敲门了。

实际上，when 从句也可以有其它的时态，但几乎也不用进行时，因为它也只是作为一个时间参照点。

例如：
When I got to the airport, the guests had left.
当我赶到飞机场时，客人们已经离开了。

When he had finished his homework, he took a short rest.
当他完成作业后，他休息了一会儿。

Why do you want a new job when you have got such a good one
already?
你已经找到如此好的工作，为何还想再找新的？
You shall borrow the book when I have finished reading it.
在我读完这本书后，你可以借阅。

while 的用法
相比于when 来说，while 从句的侧重点就不一样了。

while 从句的侧重点在于描述动作正在发生的状态，它的意思是：当while 事件正在发生的时候，另一件事如何如何。

所以，while 从句一般用的是正在进行时。

而另一件事的状态没有硬性的要求，根据具体情况而定。

例如：
1. While my wife was reading the newspaper, I was watching TV.
当妻子正在看报纸的时候，我正在看电视。

2. While Jim was mending his bike, Lin Tao came to see him.
正当吉姆修自行车时，林涛来看他。

3. While they were talking, the bell rang.
正在他们谈话的时候，上课铃响了。

4. You can’t do your homework while you’re watching TV.
你不能一边看电视一边做家庭作业。

5. While John was sitting biting his nails, I was working out a plan to get us
home.
约翰坐在那里咬指甲时，我正在制定一个回家的计划。

I felt tired out. The best moment in his career was in 2004 - he scored 41 points in a game against the Atlanta Hawks.
回顾tired out 和against 的用法
against prep. 反对，违反；靠；倚；防备adj. 不利的；对立的
【补充与against相关的搭配】
be against 反对；
go against 反对，不利于；
against one's will/wishes违背某人的意愿；
against a rainy day 未雨绸缪
练习：
Are you against it or for it? 你对此事是反对呢还是赞成?
She leaned lightly against his shoulder.她轻轻地靠在他的肩上。