八上Unit 7 Memory 语法(If条件状语从句)
【学习目标】
1.掌握unit 7 语法if引导的条件状语从句的概念，构成及应用
【课前小测】
一、单项选择。
1. Our business won’t improve ____ we offer better rvice to our customers.
A. becau B. unless C. after D. since
2.—Let’s go climbing if it_________ this Saturday.
— Good idea. But nobody knows if it _____ .
A. is fine; rains B. is fine; will rain
C. will be fine; rains D. will be fine; will rain
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3. If you take the fish out the water, it ________.
A. dies B. will die C. died D. is dying
4.If you _____ to join an educational exchange, you must apply for it first.
tray是什么意思
A. want B. wanted C. wants D. wanting
5 .In hot weather, food goes bad easily ______ it is kept in the fridge.
A. becau B. if C. unless D. since
6. — May I play the computer game?
怀疑 — No, _____ you promi to finish your homework first.
A. unless B. if C. but D. so
7. They ____ the Great Wall unless it_______ .
A. will visit; will rain B. will visit; rains C. visit; will rain D. visit; rains
8. If I find your dog, I _____ you a call. yep
A. give B. gave C. giving D. will give
9. I ________ her the answer if she ________ now.
A. can tell; will ask B. will tell; will ask C. would tell; asks D. will tell; asks
10. You _________ a toothache unless you _________ your teeth every day.
A. will get; brush B. will get; will brush C. get; will brush D. get; brush
二、用括号内所给词的适当形式填空。
1. If he _________ (come) tonight, he will meet you at the party.
2. If the weather_________ (get) wor, we will have to stay inside.
3. If the rain__________ (stop) soon, will you go to the cinema with me?
托业真题4. I ________ (buy) a new mobile phone if I ________ (have) enough money.
5. If you ________ (drop) a glass, it____________ (break).
答案：一.1-5 BBBAC 6-10 ABDDA
二.1.comes 2. Gets 3.will stop 4. will buy have 5.drops will break
【要点梳理】
一、由if引导的条件状语从句
1.主现从现 --谈论客观真理、客观事实和普遍现象时，表示条件的从句用一般现在时，用if 引导;表示结果的主句用一般现在时，这种句型简称为主现从现句型。
特别注意：从句主语是三单时，谓语动词要加s或es
蓝莓之夜插曲例如： If spring comes, trees turn green.
If you heat metal, it melts.
2.主将从现 --谈论将来可能出现的情况时，表示条件的从句用一般现在时，用if 引导; 表示结果的主句用一般将来时，这种句型简称为主将从现句型。
例如： If I am free tomorrow afternoon（从句）, I will go shopping（主句）.
If you don’t hurry up，you will be late for work.
3.主情从现 --谈论将来可能出现的情况时，主句也可用情态动词，从句用一般现在时。
excited是什么意思
例如：If it stops snowing, we can go out.
If you want to lo weight, you must/should eat less bread.
配额英文4.主祈从现 --谈论将来可能出现的情况时，主句也可用祈使句，表示提醒告诫，
从句用一般现在时。
例如：If you want to go, plea tell me.
If you like the photo, put it on the wall.
提示：
1. if从句可以放在句首，也可以放在句末。 如果把if从句放在句首，常用逗号将其与主句隔开。例如：If you study hard, you will improve your English.
You will improve your English if you study hard.2019高考文综
2. 有时，if引导的条件状语从句可以进行转换，
肯定句转换为：祈使句，and +简单句(将来时)，
If you study hard, you will get good grades. = Study hard, and you will get good grades.
否定句转换为：祈使句，or+简单句(将来时)。or表示“否则”
If you don’t hurry up, you will be late. = Hurry up, or you will be late.
二、 unless 意为“除非”，和if…not (如果……不……)的意思相近，可以互换使用。
在unless引导的从句中，通常用一般现在时，主句用一般将来时，即“主将从现”。
例如：We will have a picnic tomorrow if it does not rain.
= We will have a picnic tomorrow unless it rains.
三、as /so long as引导的条件状语从句 as /so long as意思是“只要”
So long as you're happy,I will be happy. 只要你高兴，我就高兴。
As long as you have a balanced diet, you can keep healthy.
只要你平衡饮食，你就能保持健康
四、once引导的条件状语从句
once引导的条件状语从句，意为“一旦...，就”，从句可置于主句前或后
Once you begin,never stop.一旦开始，就绝不要停止。
Maths is easy to learn once you understand the rules.
一旦你理解了规则，数学就不难学了。
butt补充：
1.连接词： if; unless; in ca, as long as; so long as; on condition that (=as long as); suppo/ supposing (=if ); provided (=if) ; but for 要不是without 如果没有 in ca of sth.万一；以防
2. 例句
1. I'll tell you the truth on condition that you promi to keep it a cret.
2. But for your help, we shouldn't have finished it in time.
3. Supposing it rains, shall we continue the sports meeting?
4. In ca I forget, I prepare a note to remind me of the things.
5. We will sign the contract provided the prize they offer is right.
【总结】
【课堂练习】
一.根据所给的汉语内容，用英语完成下列句子。每空一词，缩写算一词。
1. 如果你长时间不浇花，它们就会死。
