(完整版)(整理)中考英语专题复习：条件状语从句.

条件状语从句
我们知道 , 指引条件状语从句最常用的连词是if,由if指引的条件状语从句表示在某
种条件下某事很可能发生。

如:
If you ask him, he will help you.假如你请他帮忙, 他会帮你的。

If you fail in the exam, you will let him down.假如你考试不及格, 你会让他绝望的。

unless = if not.
Let's go out for a walk unless you are too tired.假如你不累的话让我们出去走走。

If you are not too tied, let's go out for a walk.假如你不太累让我们出去。

学习条件状语从句应注意以下几点：
（1）条件状语从句中一般不使用未来时态，尽管主句使用未
来时态，而主句用一般此刻时或此刻完成时。

【例】
I will come to see you if I have time.
我有时间，我就来看你。

If the rain stops, I shall go out for a walk.
假如雨停了，我就出去漫步。

（2）注意条件状语从句在虚假语气中的使用。

【例】
If I were to I should first of all get the experts to discuss the plan.
假如我真的想做这事，我第一会找专家们谈论我的计划。

(1)表示与此刻的状况相反，或未来实现的可能性很小， if 从句用过去式（动词 be 多用 were 这个形式），主句用“ would／should ／ could ／might ＋动词原形”。

比方：
If places_______alike, there would be little need for geographers.
A. being
B. are
C. be
D. were
假如各地方都相同，就不需要地理学家了。

（1991.6.-4,答案是Ｄ）。

在表示未来状况的虚假条件句中，还可以用“ were＋ to不定式”或“ should＋动词原形”。

Jean doesn't want to work right away because she thinks that if she ____ a job,
she probably wouldn't be able to see her friends very often.
A)has to get B) were to get
C)had got D) could have got
吉不想马上工作，因为她想：假如她获得一份工作，她就不可以常常去看她的朋友了。

(96.1-44, B对）
( 2)表示与过去的事实相反，从句用过去完成时，主句用“ would／should／could／might ＋have ＋过去分词”。

如:
If the policeman had arrived earlier, he would have seen the accident.
若是警察更早些到达，他就能见到事故了。

(3) 注意假如以上两类条件句中含有助动词、神态动词，be 或 have,则常常不用if ，而用倒装结构：
____ before we depart the day after tomorrow, we should have a wonderful dinner
party.
A) Had they arrived B) Would they arrive
C) Were they arriving D) Were they to arrive
假如我们后天走以前他们到达的话，我们就举行一次丰盛的宴会。

(97.1-34, D 对）
（3）条件状语从句中的省略。

【例】
Come tomorrow if possible.可能的话，明日来。

I will buy a DVD set if necessary.
必需的话，我就买一台DVD。

那么 , 除了 if以外,能否还有其余连词也可以指引条件状语从句呢?回答是一定的 , 不仅有 , 还有很多。

这些词因为出现的频率较小, 且用法较复杂一些, 因此不如 if为大家所熟知罢了。

下边就这些词的用法以例句的形式进行一下简单总结。

1. unless conj.除非,若不,除非在的时候
You will fail to arrive there in time unless you start earlier.假如你不早点出发 , 你就不可以及时赶到那边。

Unless it rains, the game will be played.除非下雨,竞赛将照常进行。

2. on condition(that)...在条件下, 假如
on condition (that)...指引的条件从句是主句事件发生的前提条件或独一条件。

I can tell you the truth on condition that you promise to keep a secret.我可以告诉你实情 , 条件是你答应守旧奥密。

You can go swimming on condition (that) you don't go too far from the river bank.你只有在不远离河岸的条件下才可以下水游泳。

3. supposing conj.假如,若是
supposing指引的条件从句表示一种假设条件。

Supposing it rains, shall we continue the sports meeting?若是下雨,我们的运动会还要连续举行吗?
Supposing something should go wrong, what would you do then?若是出了什么问题, 你准备怎么应付 ?
4.provided conj.若是,除非,以为条件
provided (that) +从句表示一种假设条件。

He will sign the contract provided we offer more favorable terms.假如我们提出更优惠的条件, 他就会在合同上署名。

He won't be against us in the meeting provided that we ask for his advice in
advance. 假如我们提早征采一下他的建议, 他就不会在会上反对我们。

从上述例句可以看出if, unless, on condition (that), supposing, provided等词指引的条件状语从句, 主从句条件关系分明, 结构清楚。

但有些句子, 虽没有含条件关系的连词, 却也隐含着条件关系, 这些句子常用一些词, 如 but for, without等引出一个介词结构来
表示条件 , 条件常常是虚假的, 或与事实相反的假设。

如:
but for若非,要不是
But for the rain, we should have a pleasant journey.要不是下雨,我们的旅游肯定会很快乐。

But for your help, we should not have finished in time.要不是你帮忙, 我们一定不可以及时完成任务。

练习：
单项选择
1.You will be late ____ you don’ t leave immediately.
A. unless
B. until
C. if
D. or
2.____ you keep ice-cream in a fridge, it melts.
A. Unless
B. Until
C. If
D. Or
A. will take/will die
B. take/dies
C. will take/dies
D. took/dead
4. If you _____ your timetable every night, you ____ which books to take.
A. will check/will know
B. check/know
C. will check/know
D. check/will know
5. You ____ toothache if you ____ your teeth regularly.
A. will have/clean
B. will have/do not clean
C. have/will clean
D. will have/will not clean
6. I ____ the police and complain about that noise unless it ____ soon.
A. shall telephone/stops
B. shall telephone/does not stop
C. telephone/will stop
D. telephone/will not stop
7. If you ____ the tickets with you, we ____ to enter the cinema.
A. do not take/will not allow
B. take/will not allow
C. do not take/will not be allowed
D. take/will not be allowed
8. If the fish ____ from the bird’ s mouth, the bird will swallow it.
A. won’t remove
B. won’t be removed
C. doesn’ t remove
D. isn ’ t removed
9. If the rain doesn’t stop, you can enjoy ____ here for another day.
A. stay
B. to stay
C. staying
D. stayed
10. Don ’ t put your umbrella over there, or you will forget ____ it home.
A. take
B. to take
C. taking
D. took
11.____ I know the money is safe, I shall not worry about it.
A. Even though
B. Unless
C. As long as
D. While
12. Don't be afraid of asking for help ____ it is needed.
A. unless
B. since
C. although
D. when
13. I would appreciate it ____ you call back this afternoon for the doctor's
appointment.
A. until
B. if
C. when
D. that
14. You will succeed in the end ____ you give up halfway.
A. even if
B. as though
C. as long as
D. unless
15.You will be late ___ you leave immediately.
A. unless
B. until
C. if
D. or
16. You will be late for school _______ you leave now.
A. if
B. when
C. because
D. unless
17. If I get a job, I _________ as a teacher.
A. work
B. will work
C. works
D. worked
18. If it________ tomorrow, we’ ll go to the park.
A. will not rain
B. rains
C. doesn’ t rain
D. isn ’ t rain
19.You will do much better ________ you are more careful with oyur spelling.
A. if
B. before
C. although
D. unless
20. All of us will be happy _____ you can come with us.
A. while
B. if
C. but
D. or
答案：
CABDB
BACBA
CDDDA
DBCAB
将由 unless与if not 构成的句子进行改写。

1.You won’ t pass your exams unless you study hard.
2.We’ ll play outside this afternoon unless it rains.
3. If he doesn’ t come in the next time minutes, I’ m leaving.
4.Leave without me unless I phone.
5.You can ’ t send a letter unless you know the address.
6. You can ’ t go in if you’ re not a member.
7. Don’ t include them if they don’t reply.
答案：
1.You won’ t pass your exams if you don’ t study hard.
2.We’ ll play outside this afternoon if it doesn’ t rains.
3.Unless he comes in the next time minutes, I’ m leaving.
4.Leave without me if I don’ t phone.
5.You can ’ t send a letter if you don’ t know the address.
6.You can ’ t go in unless you are a member.
7.Don’ t include them unless they reply.
有所给词的合适形式填空。

make complain suffer open understand hurt
turn explain study burn pass buy hike
get has fall
1.
2.If you _________ the key, the door___________.
3.
4.If we _________ too much noise, the neighbours __________.
5.He won’ t be able to go to ___________ if the typhoon__________.
6.If you _________ the forests, the environment__________.
7.James _________ himself if he__________ off that ladder.
8.The students ________ their exams if they _______ hard.
9.I ________ a new car if I ___________ a pay rise.
10.
11. She ________ it if you ________ it more clearly.
答案：
1. turn will open
2. make will complain
3. hiking gets
4. burn will suffer
5. will hurt falls
6. will pass study
7. will buy have
8. will understand explain。