牛津译林版九年级上册9A Unit5 Grammar原因状语从句讲解+提优练习题(无答案)

9A Unit5语法专项：-----because,since,as 引导的原因状语从句
1.原因状语从句通常由because, since, as引导。

【例】He didn’t come to school because he was ill.
As it is raining, we shall not (不得；不应该)go the zoo.
Since you can’t answer the question, I’ll ask someone else.
2.(1)because表示直接原因，语气最强。

Because引导的原因状语从句多放在主句之后。

回答由why提出的问题，只能用because而不能用since，as。

【例】------Why aren’t going there?------Because I don’t want to.
(2)because不能与并列连词so同时在句中使用。

[任务型阅读-两者互换]
She was late for school because she missed the bus.
= She missed the bus, she was late for school.
(3)because和because of 也有明显的区别。

because后面要跟从句，而because of 后面要跟名词短语。

【例】He is late for school it rains heavily.
He is late for school the heavy rain.
3.As和since语气较弱，一般用来表示明显的原因。

由as和since引导的原因状语从居多放在句首。

【例】As he has no car, he can’t get there easily.
Since we have no money, we can’t buy it.
总结：since conj./prep 自从...起（出现since引导的时间状语，主句现完。

）
conj.既然，因为
as conj.当..时，随着；因为；正如prep.作为
拓展：for作为并列连词，也有“因为”之意。

巩固练习：
1.—Why didn’t you email me to tell me about this, Jack?—______ I was too sad at hat time.
A. For
B. As
C. Since
D. Because
2.---______ do you buy so many film tickets for?
--- Because all the members of the Film Club are going to the cinema together.
A. Why
B. What
C. How
D. Who
3.He didn’t go to work _______ it was raining ______.
A. because, heavy
B. because of ,heavily
C. because, heavily
D. because of, heavy
4.______everyone is here, let’s start our meeting.
A. Because
B.Since
C.Because of
D. As
5.Daniel decided to play the violin at the art festival,_____ he is good at it.
A. because
B. since
C. though
D. because of
6.Jack still came to work _______he was ill.
A. as
B. because
C. though
D. since
7._______he is only 12, he often goes to the old people’s home to perform plays for the old people
as a volunteer.
A. Since
B. Though
C. If
D. Because
8._________he likes the sounds of nature, he uses them a lot in his music.
A. Though
B. As
C. Because
D. With
9.---- Could you tell me ______ yesterday ?
----Because my bike was broken on the way home.
A.why you came late
B. why do you come late
C. why did you come late
D. why you come late
10.I knew nothing about yesterday's accident Millie told me about it.
A. when
B. as
C. until
D. after
11.---_______ he is rich, ______ there is something that he can't buy.
--- Yes. Such as friendship and love.
A. Because; /
B. Though; /
C. Because; so
D. Though; but。