Unit 10 If you go to the party，you’ll have a great time!
1．I think…句型,是一个含有宾语从句的主从复合句，意为“我想…，我认为…”。
注意：后面的从句里如果有否定含义，往往把否定词由从句移到主句，这叫否定转移。
如：I don,t think I,m going to stay at home .我想我明天不会呆在家里
I don’t think I ‘ll wear jeans to the party .我认为我不会穿牛仔裤参加晚会。
2. If we have it today, half the class won't come.
half the class=half of the class"一半的同学",
half作名词，意为“一半，半个”复数形式是halves.
half常用于“half a/an+名词”结构；如: half a cake , half an apple
表示“几个半……”时，可用“数词+名词+and a half”或“数词+and a half+名词（复数）”结构。如：four hours and a half = four and a half hours
3. if条件句
以 if引导的条件状语从句 。注意：当主句是将来时的时候，从句要用一般现在时。
如: If it rains tomorrow ，we,ll stay at home.
If we have it today, half the class won't come.
If it rains tomorrow, I shall not climb the hills.
If I go to college, I will never become a great soccer player.
注意宾语从句中的if与条件状语从句if的区别。宾语从句中的if“是否”引导宾语从句，时态需根据语境确定。
I don't know if it will rain tomorrow. 我不知道明天是否会下雨。
I don’t know if it rained yesterday.我不知道昨天是否下雨了。
仔细观察下列例句，然后总结归纳关于if 引导的条件状语 从句的用法。
1.If it rains next Sunday, we won’t go for a picnic.如果下周日下雨，我们就不去野餐了。
2.If you go to the party, you will meet Uncle Zhang.如果你去参加聚会，就会遇到张叔叔。
3.I’ll ask the teacher for help if I don’t understand.如果我有不懂的知识，就会向老师求助。 4.We’ll plant trees in the mountains if it is fine tomorrow.如果明天天气睛朗，我们就要去植树。
5.Put up your hand if you have any questions to ask.如果你有问题，请举手。
6.If I get there early, I can see the doctor soon.如果我早到这儿，我就能很快看病。
if连接了一个条件状语从句，表示假如有从句的动作发生，就会有主句的动作发生。
通常情况下，主句用一般将来时，if引导的条件状语从句要用_________时态；
由if 引导的条件状语从句既可以放在主句之______，如例句1、2、6；也可以放在主句之_______，如例句3、4、5 从句如果位于主句之前时，常用_________将其与主句隔开，如例句1、2、6
若主句是祈使句，if引导的条件状语从句仍用____________时态。如例句_______;
练一练
用所给词的正确形式填空。
1. The students will go to the Summer Palace if it (not rain)
2 If he (walk) to school, he’ll be late.
3. If she likes it, she (read) it soon
4. If you play computer games on weekdays, you (be) tired.
5. If you (work) hard, your dream will come true.
6. If she (study ) hard, she will go to Beijing University.
7. If it (rainy) tomorrow, I will play the piano.
8 If I (have) some money, I (buy) a new house.
9. I’m sure if he _____(go) to the party, he________ (have) a great time.
10. If the rain _______(stop) tonight, we will go to the cinema.
11. I’ll buy a computer if I ______(have) enough money.
12. You _________(not get) nervous if you _____(do ) enough exercise.
13. If she ____ (be) kind to me , I __________(not argue) with her.
unless的用法
Unless 除非, 如果不
引导条件状语从句，含有否定意义，相当于if条件状语从句的否定形式。所以unless = if not。如：
Unless you take more care, you’ll fall into the river
=If you don’t take more care , you’ll fall into the river.
如果不多加小心的话，你将会掉进河里。
My baby sister never cries unless she is hungry.
=My baby sister never cries if she isn’t hungry
我那刚出生的妹妹除非饿了，否则她是从来不哭的。
Don’t promise anything unless you’re 100 per cent sure.
=Don’t promise anything if you aren’t 100 per cent sure.
不要作任何的许诺, 除非你有百分百的把握。
Unless bad weather stops me, I will run every day.
=If bad weather doesn’t stops me , I will run every day.
除非坏天气作梗，每天我都跑步。
We'll be late unless we hurry up.
=we’ll be late if we are not hurry up
我们要不加快些，就会迟到了。
You'll not pass the exam unless you work hard
= You'll not pass the exam if you don’t work hard
除非你努力学习，否则这次考试你将不及格。
You'll miss the bus unless you walk more quickly.
= You'll miss the bus if you don’t walk more quickly.
除非你走快一点，否则将赶不上公共汽车。
You won't hear anything unless you turn off the TV.
= You won't hear anything if you don’t turn off the TV
除非你把电视关掉，否则你是不会听到任何东西的