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Unit 10 If you go to the party you’ll have a great time
单元语法小专题(Grammar Focus)
语法精讲
if引导的条件状语从句
条件状语从句通常由连词if引导，意为“如果；假如；倘若”，表示在某种条件下，很可能会发生某事或不发生某事。
1．if条件状语从句的位置
在 if 引导的条件状语从句中，if 条件句位置比较灵活，可放在主句前面也可放在主句后面。若放在主句前，从句后面一般要用逗号和主句隔开。如：
If he doesn't feel tired，he will visit the museum.＝He will visit the museum if he doesn't feel tired.如果他感觉不累，他就会去参观博物馆。
2．if条件状语从句的时态搭配
(1)当主句用一般将来时，if 引导的条件状语从句要用一般现在时。如：
If it rains tomorrow，I won't climb the hills.如果明天下雨，我就不爬山。
(2)当主句中含有can，may，must等情态动词时，if 引导的条件状语从句要用一般现在时。如： We can win the basketball game if he joins us.如果他加入我们，我们就能赢这场篮球赛。 (3)当主句是祈使句时，if 引导的条件状语从句要用一般现在时。如：
Help your mom with the housework if you finish your homework early.如果你完成作业早，就帮你的妈妈做家务。
if条件状语从句用法歌诀：
if 条件句不一般，几个要点记心间； 条件句，放在前，逗号要放句中间； 条件句，表可能，主句多用将来时； 条件句，表事实，主句常用现在时。 3．与其他句式之间的转换
(1)借助“祈使句＋and/or＋一般将来时的句子”这一句型来转换。and在句意上表示顺承关系，or表示转折关系。如：
If you get up early，you'll get there on time.＝ Get up early，and you'll get there on time.＝Get up early，or you won't get there on time.早点起床，你就会准时到那里。
(2)借助介词without或with来转换条件状语从句。如：
If there is no water，fish will die.＝Fish will die without water.如果没有水，鱼就会死。
If you help me，I'll finish the work soon.＝With your help，I'll finish the work soon.如果你帮助我，我就会早点完成工作。
(3)if…not引导的条件状语从句，可以借助连词unless来改写。如：
You will be late if you don't go there by bus.＝You will be late unless you go there by bus.如果
你不乘公共汽车你就会迟到。语法精练
Ⅰ.用括号内所给单词的适当形式填空。
1．If it rains tomorrow，I will__stay(stay) at home.
2．He will take a trip to Beijing if he isn't(be not) busy next week. 3．Please tell Li Jun about it if he comes(come) back.
4．If you don't wear your school uniform to the party，the teachers won't__let(not let) you in. 5．She won't__go(not go) shopping with her parents if it snows this afternoon. Ⅱ.单项选择。
(A)6.—Do you know when he will come back tomorrow?
—Sorry，I don't know.When he ________ back，I'll tell you. A．comes B．will come K12精品文档学习用
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C．come D．may come
(D)7.Mary will go to Sanya if she ________ a five－day trip. A．have B．had
C．will have D．has
(A)8.What will you do if you ________ to the party without invitation? A．go B．went C．going D．will go
(D)9.If I eat too much food，I ________ too fat. A．am B．was C．will D．will be
(B)10.I'll give the book to him if he ________ here next Sunday. A．will come B．comes C．is coming D．came
Ⅲ.同义句转换，每空一词。
11．Study hard，or you won't pass the exam. If you study hard，you will pass the exam. 12．Take a taxi，and you'll catch the train. If you take a taxi，you'll catch the train.
13．If you don't help me，I can't catch up with the others. I can't catch up with the others without your help． 14．We will be late for the meeting if we aren't quick. We will be late for the meeting unless we are quick． 15．If you are late，the teacher will be angry. Don't be late，or the teacher will be angry.
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