Unit10 if条件状语从句讲义- 2024-2025学年人教版八年级英语上册

条件状语从句 If引导的条件状语从句的位置 if引导的条件状语从句，可放在主句的前面或后面。 即：1. 主句+if从句 2. If从句，+主句 If引导的条件状语从句的含义 If 是连词，意思是如果；假若；倘若 通常表示假设，表示将会发生和可能发生的事，或进行提醒警告。 If引导的条件状语从句的时态 1. 当主句用一般将来时时，if引导的条件状语从句用一般现在时。(即主将从现) 2. 如果主句是祈使句，那么从句通常也是一般现在时。 (即主祈从现) 3. 如果主句是含有must，can，may 等情态动词时，根据需要从句多用一般现在时。(即主情从现) 4. 表示真实条件、客观真理、自然现象、定理定义、 民间谚语等， 句型是：If + 句子 （一般现在时），+ 主句 （一般现在时）.(即主现从现) 注意： if还可以用于宾语从句中，表示“是否”，= whether，引导宾语从句，时态需根据语境确定。 if引导的条件状语从句的结构和用法 一、有些句子可与含if的条件状语从句互相转换。 （1）祈使句 + and/or + 陈述句。 Hurry up, or you’ll miss the train. = If you don’t hurry up, you’ll miss the train. （2）借助with或without。 You can’t drive the car with the door open. = You can’t drive the car if the door is open. 二、由连词if引导的条件状语从句, 主句不能用be going to表示将来, 而应该用shall, will。 If you leave now, you are never going to regret it. (错误) If you leave now, you will never regret it. (正确) 三. unless(相当于if...not, 除非，如果不), as long as(只要)也可以引导条件 状语从句。 If it doesn't rain tomorrow, we'll go hiking. =We'll go hiking unless it rains tomorrow. But I think friends are like books --- you don't need a lot of them as long as they're good. 4、 表示真实条件、客观真理、自然现象、定理定义、 民间谚语等， 句型是：If + 句子 （一般现在时 ），+ 主句 （ 一般现在时）.(即主现从现)。 If water is heated,it turns to steam. If people don't get enough sleep, their thinking ability is reduced. 当堂检测 一、单项选择 1. I think my mother ________ if she _______ free tomorrow. A. will come; is B. comes; is C. comes; will be D. will come; will be 2. If she likes it, she _______ it soon. A. read B. reads C. will read D. reading 3. He will go out with you after he _______ his homework. A. finishes B. will finish C. is finishing D. finish 4. I will send you an e-mail as soon as I ______ in Canada. A. arrive B. arrived C. am arriving D. will arrive 二、用所给词的适当形式填空 1.If he _______(come) to the party, he will have a good time. 2.We don’t know if it ________(rain) tomorrow; if it ________(rain), we ________(not go) out. 3.If it’s sunny tomorrow, Mary ___________(visit) the Great Wall. 4.If you _____(come) at 4:00 in the afternoon, I _______________(begin) to be happy at 3:00. 3、 同义句转换 1. Hurry up, or you will not catch the bus. _______ you ______ hurry up, you will not catch the bus. 2. Finish your homework now, and you can watch TV. ______ you ______ your homework right now, you ______ watch TV. 3. The fish may die without enough water. _____the fish ______ have enough water, it ______die. 4、 翻译句子 1. 如果你想取得好成绩，你必须努力学习。 ________________________________________________________ 2. 世上无难事，只要肯登攀。 ________________________________________________________ 3. If winter comes, can spring be far behind? ________________________________________________________ 课后练习 一、单项选择 1.If you are late for class, the teacher ______ angry. A. is    B. was    C. will    D. will be 2. How _______I ______？ A. am; get there 　B. can; get to there C. can; get there　 D. will; get to there 3. If you watch TV now, you _________the homework tonight. A. don’t finish B. won’t finish C. didn’t finish  D. aren’t finish 4. I am surprised _________that you won’t go to college. A. to hearing  B. hearing　　C. hear D. to hear 5. I like football very much. I want _________a football player. A. is　　   B. am　　　C. to be　 D. be 二、填空 1. I’m sure if he _____(go) to the party, he _______ (have) a great time. 2. If the rain ______ (stop) tonight, we will go to the cinema. 3. I’ll buy a computer if I ______(have) enough money. 4. You _________(not get) nervous if you _____(do) enough exercise. 5. If she ___ (be) kind to me , I _____________(not angry) with her. 6. I want to know if he _________(come) tomorrow, if he _______(come), I __________(give) the massage to him. 7. If you _____(pay) more attention to that, he ________ (not get) hurt. 8.We’ll be punished if we _______(break) the rules. 9. If it ____(be) cloudy, they _______(not go) there by air. 10. Please let us know if he _________(arrive) tomorrow. 11. Shall I say “Hello” when the foreigner ______(come) into the classroom? 12. He’ll get better grades if he ____________ (study hard) 13. If you work really hard, you ____________________ (be famous and rich). 三、填空 1. If you exercise more, you ______ (be) much healthier. 2. If it ______ (rain) tomorrow, they _________ (not play) soccer after school. 3. You should see a dentist if you _____ (have) a toothache. 4. If he _____ (walk) to school, it ________ (take) him too much time. 5. If you ________ (not go) to bed earlier, you _______ (feel) tired in the morning. 6. If it __________ (not rain), he ________ (play) basketball with me tomorrow. 7. If Uncle Ian ______ (come), I ________ (call) you up. 8. Please wake me up if he _______ (come) back. 四、选词填空。meeting, video, chocolate, taxi, upset, advice, organize 1. If you walk there, you’ll be late for the ________. 2. If they watch a _______ at the party, some students will be bored. 3. I don’t know what to do, can you give me some ________? 4. What will happen if she _________ a soccer game on Saturday? 5. If she doesn’t come home on time, her parents will be ________. 6. If it rains tomorrow, we’ll take a _______ there. 7. If he eats too much _________, he’ll be very heavy. 学科网（北京）股份有限公司 $$