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课件网) 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...= ... ...
