Unit 10 If you go to the party, you'll have a great time!语法课件(共27张PPT)人教新目标(Go for it)版英语八年级上册

(共27张PPT)
Unit 10
If you go to the party, you’ll have a great time!
If 引导的条件状语从句
1. 定义 从句表示主句动作发生的前提、条件、假想和推测等。
2. 意义 条件状语从句表示主句发生的条件，表示假如有从句的动作发生，就会有主句动作的发生。
3. 句子构成 (1) if 引导的条件状语从句+主句If you don’t hurry up, you’ll be late.
(2) 主句+ if 引导的条件状语从句You’ll be late if you don’t hurry up.
一、基本概念
二、主句与从句的时态
当主句为以下三种情况时，条件状语从句用一般现在时表示将来：
1. 当主句为一般将来时时： If he comes, he will bring his violin.
2. 当主句的谓语中含有can, may, must等情态动词时： If you want to lose weight, you must eat less meat.
3. 当主句为祈使句时: If you are not strong enough, please don't take part in such an activity.
三、句型转换
1. 借助“祈使句+and/or+句子(一般将来时)”这一句型来转换 If you study hard, you will pass the exam easily.= study hard, you will pass the exam easily.
2. 借助without或with来转换条件状语从句 If there is no water, fish will die.= Fish will die without water.
If I get up at 7:00, I will be late.
If I am late, the teacher will be angry with me.
If the teacher is angry with me, I will be sad.
主句
从句
从句
从句
主句
主句
__________________
I will see a doctor if I’m ill.
Look and say
If I’m ill,
I will see a doctor.
从句可放在主句之前或之后，但是放在主句之前须有逗号隔开
If I get up at 7:00, I will be late.
If I am late, the teacher will be angry with me.
If the teacher is angry with me, I will be sad.
I will be late if I get up at 7:00.
The teacher will be angry with me if I am late.
I will be sad if the teacher is angry with me.
If I am late, the teacher will be angry with me.
三， 含if条件状语从句的主从复合句的时态
1. if 条件状语从句中，主句用一般将来
时，从句用___________表示将来
________原则。
主将从现
一般现在时
It will rain tomorrow.
I will stay at home.
If it _____ tomorrow, I _____ _____ at home.
rains
will
stay
He won’t study hard.
He will fail in the exam.
If he _______ study hard, he ____ _____ in the exam.
doesn’t
will
fail
We will go to the park if it _______ ______ (not rain) tomorrow.
doesn’t
rain
If I have much money, I will…………
travel all over the world.
buy lots of delicious food.
2. if 条件状语从句中，如果主句有
must，can，may 等情态动词，从
句用___________。
You must stop if the traffic light ____ (be) red.
is
一般现在时
“主情从现”
If you feel hungry, you should eat something.
If you feel tired, you must have a rest.
He can go home if he ________ (finish) his homework.
finishes
Don’ t wait for me if I _____ (be) late.
Put up your hands if you _____ (have) any questions.
3. if 条件状语从句中，主句是祈使句，
从句用____________表示将来。
_________原则。
am
主祈从现
一般现在时
have
注意事项
1. 在if引导的条件状语从句中，当主句是一般将来时时，不能够使用be going to结构，而要用will。
I’ll help you with your English if I am free tomorrow.
2. 在if引导的条件状语从句中不能够使用some，而要用any。
If you have any questions to ask, please come to my office.
if的反义词：if...not...=unless,意思是：“如果不，除非”
I won’t go there unless I hear from you.(同义句)
I won’t go there _____ I _____hear from you.
if don’t
I won’t go to the party if I am not invited. (同义句)
I won’t go to the party_____ I am invited.
unless
变换：
1.有if引导的条件状语从句的复合句中，当主句和从句的主语均为you时，可转换为“祈使句，and+简单句”或“祈使句，or+简单句”
You can pass the exam if you work hard.
，and you will pass the exam.
If you don't hurry up,you will be late again.
Hurry up, you will be late again.
Work hard
or
2. 借助介词with 或without来转换。
If you help me, I’ll finish my job soon.
　　
——————— , I’ll finish my job soon.
　　
　　If there is no water, fish may die.
　　
Fish may die ——————　　
With your help
without water
If it ____ (be) cold tomorrow, I will wear my sweater.
is
If I _______________(not understand）, I will ask my teacher for help .
don’t understand
If you _____ to the party, you’ll have a great time.
A. will go B. went C. go D. going
c
练习
【即学即练】
用所给词的正确形式填空
1. If I ________ (be) free tomorrow, I will read a book.
2. If it rains tomorrow, I _______ (stay) at home.
3. What ________ (happen) if you are late for school
4. Don’t tell her if she ________ (not) know.
5. If he _______(have) enough time tomorrow, he ________ (meet) you at his office.
【参考答案】1. am 2. will stay 3.will happen 4.doesn’t 5. has; will meet
4
1.If I __________(copy ) your homework , I will cheat myself .
2. If she _______________(not get ) up early , she’ll miss the early bus .
3. If your mother_______ (buy) the book for you , it will be good for your study.
copy
doesn’t get
buys
4. If you ____________(not work ) hard , you _________(not pass) the exam.
5. If your brother ____________(break) the window , he will feel very sorry for that .
don’t work
won’t pass
breaks
6. If she _______(not be) interested in math, she will find it very boring .
7. If you _________(get ) high scores, your parents will be proud of you .
8. If you _________(be) happy , we will be happy .
isn’t
get
are
9. – What are you going to do tomorrow
--We’ll go to the library tomorrow if it ___.
A. isn’t rain B. rain
C. won’t rain D. doesn’t rain
10. What will you do if you _____ to Beijing
A. go B. went C.going D. will go
A
D
Thank you