初中英语原因状语从句 课件 (共18张PPT)

(共17张PPT)
原因状语从句
原因状语从句指在句中用来说明主句原因的从句。
I do it because I like it.
我做这件事是因为我喜欢。
As it is raining, you'd better take a taxi.
既然在下雨， 你最好乘出租汽车。
引导词
because , as , since（既然）, now(that)（既然）, when（既然）, seeing (that) （由于，鉴于）, for（为）,
considering (that)（考虑到）, given (that) （考虑到）等
I don’t want to talk with him because he always tells lies.
我不想和他交谈因为他总是说谎。
I can’t get to sleep because of the noise outside.
由于外面声音嘈杂我睡不着。
Since/As we’ve no money, we can’t buy it.
由于我们没钱，我们不能购买它。
Seeing that it's raining, we'd better stay indoors.
既然外边在下雨，我们最好待在室内。
Now that you are here, you'd better stay.
既来之，则安之。
辨析下列引导词
辨析点一：because不能与so连用 一山不容二虎
Because it was raining, we stayed at home. （√）
It was raining, so we stayed at home. （√）
Because it was raining, so we stayed at home. （×）
因为下雨，所以我们得呆在家里。
辨析点二：because与 because of
Because引导的原因状语从句有时可与because of 介词短语转换，because of后加名词性短语，because后加句子。
He can't come because he is ill.
= He can't come because of his illness. 他因病不能来。
I said nothing about it because his wife was there.
= I said nothing about it because of his wife's being there.
因为他妻子在那儿，我对此事只字未提。
辨析点三：比较because, since,as和for的区别
1)because从句位于句首时要用逗号分开，放在句末时，可不用逗号分开。
because表示直接原因， 语气最强， 最适合回答why引导的疑问句。
We went by bus because it was cheaper.
2) since从句一般放于主句之前表示已知的、 显然的理由(翻译成“既然”= now that )， 较为正式， 语气比because弱。
Since you don't trust him, you should not employ him.
既然你不信任他，你就不应该雇佣他。
3)as 从句表示附带说明的“双方已知的原因”，含有对比说明的意味，语气比since弱， 较为正式， 位置较为灵活(常放于主句之前)。
I went to bed early, as I was exhausted.
因为太累了，所以我睡得比较早。
4) for引导的句子只提供一些辅助性的补充说明， for引导的并列句只能放于主句之后并且必须用逗号将其与主句隔开。
He could not have seen me, for I was not there.
他不可能看见我了，因为我没在那。
相比较而言：
as和for引导的主、从句，二者处于平等位置；
because引导的从句显得比主句重要，强调原因；
since引导的从句显得次要，而主句重要，以说明将要做什么事。
用because, as, since, for 填空：
We'll have to go to bed early _________ we'll start off early tomorrow.
___________ you know all about it, tell me please.
____________ all the seats were taken, I had to stand.
because
Since
As
He must be at work, __________ the light in his office is still on.
Lily didn't go to school ___________ she was ill.
=_________________________________________________________.
for
because
Lily didn't go to school because of her illness.
Thank you