if引导的条件状语从句

1、if引导的条件状语从句 if引导的条件状语从句 条件状语从句是在复合句中作条件状语的句子。表示假如有从句的动作发生就会有主句的动作发生。条件状语从句常由从属连词if引导。 if引导的条件状语从句使用须知： 一、位置 if引导的条件状语从句，既可放在主句之前也可放在主句之后。当从句置于主句之前时，常用逗号与主句隔开。例如： You will catch the bus if you get up early. =If you get up early, you will catch the bus. 如果你早起的话，就能赶上公共汽车。 二、时态 应遵循主、从句时态呼应的原则。当主句是一般现在时

2、(包含祈使句和含情态动词can, may, must等的句子)，从句也用一般现在时。例如： You must see the doctor if you are ill. 如果你生病了，你必须去看医生。 If you want to go skating, wear warm clothes. 如果你想去滑冰，穿上暖和点的衣服。 如果主句是一般将来时，从句必须用一般现在时。例如： You will be late for school if you get up late. 如果你起晚了，你上学将迟到。 If it rains tomorrow, we wont go to the Great

3、 Wall. 如果明天下雨，我们就不去长城了。 三、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。例如： Ill help you with your English if I am free tomorrow. 如果明天我有空，我会帮你学英语。 2. 在if引导的条件状语从句中不能够使用some，而要用any。例如： If you have any questions to ask, please come to my office. 如果你有问题要问的话，请到我办公室来。 四、同义句转换 if引导的条件状语从句可以转

4、换成简单句，其方法如下： 1. 借助“祈使句+and/ or+简单句”。其中and表示句意顺承，or表示转折。例如： If you work hard, youll pass the exam. =Work hard, and youll pass the exam. 如果你努力学习，你就会通过考试。 If you dont hurry up, youll be late. = Hurry up, or youll be late. 如果你不快点，你将会迟到。 2. 借助介词with 或without来转换。例如： If you help me, Ill finish my job soon.

5、 =With your help, Ill finish my job soon. 如果你帮我，我将很快完成我的工作。 If there is no water, fish may die. = Fish may die without water. 如果没有水，鱼可能会死。 【巩固练习】 一、用所给动词的适当形式填空。 1.If I run every day, I _(be) healthier. 2.If you _(not eat) healthily, your body wont be well. 3.If you sleep well, you _(feel) better. 4

6、.If you _(relax), youll sleep better. 5.Do more exercise, and it will make your mind and body _(work) better. 二、完成句子（一空一词）。 1如果你要过马路，不要乱跑。 _ _ around if you cross the road. 2明天如果下雨的话，我们将呆在家里。 We _ _ at home if it _ tomorrow. 3. 如果你能说好英语的话，你就可以容易地与外国人交谈。 If you can _ English well, you _ _ _ foreigner

7、s easily. 4.如果你对别人好，人们也会对你好。 If youre nice to people, they _ _ _ to you, too. 5.如果学生不对考试如此担心的话，他们会更开心的。 If students dont worry about exams so much, they _ _ _. 三、同义句转换。 1. Study hard, or you wont pass the exam. If you study hard, you _ _ the exam. 2. Take a taxi, and youll catch the train. _ you _ a

8、 taxi, youll catch the train. 3. If you go to bed early, you wont feel tired in the morning. _ _ _ early, _ you wont feel tired in the morning. 4. If you dont work hard, your teacher will probably be angry. _ _, _ your teacher will probably be angry. 5. Breathe deeply for one minute, and youll feel

9、relaxed. _ you _ deeply for one minute, you _ _ relaxed. 四、阅读下面的广告，然后用“if., .will.”句式回答问题。 Travel Brochure Cheap Cheap Cheap. Beijing for the weekend. 3D/2N. Book Now. Five Star HotelSave 50% Four Star HotelSave 40% Three Star HotelSave 30% Book before December 31st. Breakfast Included. City Tour 50

10、RMB. Visit the Great Wall 100 RMB. 1. How much will you save if you stay at the Four Star Hotel? _ 2. How much will you save if you stay at the Three Star Hotel? _ 3. What will happen if you book after December 31st? _ 4. How much will you have to pay if you want to go on the City Tour? _ 5. How muc

11、h will you have to pay if you want to visit the Great Wall? _ Key: 一、1. will be2. dont eat3. will feel4. relax5. work 二、1. Dont run2. will stay, rains3. speak, can talk with 4. will be nice5. will be happier 三、1. will pass 2. If, take3. Go to bed, and4. Work hard, or5. If, breathe, will feel 四、1. If I stay at the Four Star Hotel, I will save 40%.2. If I stay at the Three Star Hotel, I will save 30%. 3. If I book after December 31s