第13讲 八上新知专题 if 引导的条件状语从句 【暑假辅导班】2021 年新八年级英语暑假精品课程（牛津译林版） 第一部分 语法 if 引导的条件状语从句表示在某种条件下某事很可能发生。 If we pay much attention to the earth, we’ll have a better world. 如果我们多关爱地球，就会拥有一个更美好的世界 If it rains tomorrow, what shall we do? 如果明天下雨，我们怎么办？ If you ask him, he will help you. 如果你请他帮忙，他会帮你的。 If you fail in the exam, you will let him down. 如果你考试不及格，你会让他失望的。 注意：if 还可以引导虚拟条件句，表示不可实现的条件，从句中多用一般过去时或过去完成时。 What would happen if there were no water? 如果没有水会怎样？ 引导条件状语从句最常用的连词是 if，常见的 if 条件状语从句表示在某条件下，某事很可能发生，条 件是可能存在的，主句中某种情况发生的概率也是很高的。如： If you ask him, he will help you. 如果你请他帮忙，他会帮你的。 If you fail in the exam, you will let him down. 如果你考试不及格，你会让他失望的。 If you have finished the homework, you can go home. 如果你作业做完了就可以回家了。 另外，if 从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设。从句 多用一般过去时或过去完成时，表示对现在或过去的一种假设。如： If I were you, I would invite him to the party. 如果我是你，我会邀请他参加聚会。 I would have arrived much earlier if I had not been caught in the traffic. 要不是交通堵塞，我本会来得早一些。 6. if 条件句的时态搭配 （1）if 从句用一般现在时，主句用一般将来时。 If he runs he’ll get there in time. 如果他用跑的，他就会及时赶到那儿。 The cat will scratch you if you pull her tail. 如果你拉猫的尾巴，它就会抓你。 （2）if 从句用一般现在时，主句用 may/might/can。 If the fog gets thicker the plane may/might be diverted. 如果雾再大一些，飞机可能就会改在别的机场降落。 If it stops snowing we can go out. 如果雪停了，我们就可以出去。 （3）if 从句用一般现在时，主句用 must/should。 If you want to lose weight you must/should eat less bread. 如果你想减肥，你必须少吃面包。 （4）if 从句用一般现在时，主句用一般现在时。 If you heat ice it turns to water. (也可用 will turn)如果把冰加热，它就会化成水。 （5）if 从句用现在进行时，主句用一般将来时。 If you are looking for Peter you’ll find him upstairs. 如果你是在找彼得，上楼就会找到他。 【知识拓展】 1. 在以 when，before，as soon as 等引导的时间状语从句，也适用＂主将从现＂原则，即如果主句是一 般将来时，从句则用一般现在时。 I’ll tell her the good news when she comes back. 当她回来的时候，我将把这个好消息告诉她。 she will give you a call as soon as she returns. 她一回来就会给你电话。 2.If 条件句的同义句：祈使句，and /or+将来时态的陈述句。 Work hard, and you will make great progress. = If you work hard, you will make great progress. 如果你努力学习，你就会取得大的进步。 Hurry up, or you will be late. =If you don’t hurry up, you will be late. 如果你不快点，你就要迟到了。 【巧学妙记】 ＂ if ＂ 引导的条件状语从句的记忆口诀 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。 条件句表真实，主将从现要遵从； 条件句非真实，虚拟语气用到位。 第二部分 if 引导的条件状语从句专项训练（含解析） 一、单项选择 1．—Does Ted tell you if he _____ next Sunday? —No, he doesn’t. But if he _____ , I will give you a ring. A．comes; will come B．comes; comes C．will come; comes 2．If Nancy ________ the exam, she will go to Australia for English study. A．pass B．passed 3．We will go for a picnic if it A．doesn’t rain C．passes tomorrow. B．wasn’t rainy C．won’t rain D．wasn’t raining 4．We will stay at home ________ it rains tomorrow. A．so B．if C．but D．because 5．If it ________ tomorrow, would you like to have a picnic with me? A．don’t rain B．doesn't rain 6．—I don't know if they A．visit;snows C．won't rain D．didn’t rain the Great Wall next Sunday.—They won't go there if it B．visit;will snow . C．will visit;will snow D．will visit;snows 7．You will pass the final exam. ________ you work harder. A．if B．although C．so D．unless 8．You will have fun if you ________ tomorrow. A．go hiking B．will go hiking C．went hiking D．are go hiking 9．If you __________take my advice, you __________reget（后悔）later. A．don’t...will B．won’t...will C．don’t...won’t D．won’t...don’t. 10．--- May I go to the cinema with Tom tomorrow, Mum? --- Of course, if your homework A．finishes by then. B．will finish 11．— Do you know if it C．is finished D．will be finished tomorrow? — I am not sure. It may snow if the temperature below zero. A．snows; will drop B．will snow; will drop C．will snow; drops D．snows; drops 12．I don’t know if he ______ here tomorrow. If he _______ , I will tell you. A．comes; comes B．will come; will come C．will come; comes D．comes; will come 13．You made the same mistake again. You won’t get better ________ you don’t learn from your lesson. A．so B．though C．if D．until 14．She has too many dresses. _________ you want to give her a surprise, you can buy something else. A．If B．So C．Or D．But 15．If you _____ out all the candles in one go, the wish ______ true. A．will blow; will come B．blow; will come C．will blow; comes comes 16．Life is like a mirror. If you smile at it, it ______ back. A．has smiled B．will smile C．smiled D．is smiling 17．If he ________ harder, he ________ up with his classmates soon. A．study, catch B．studies, catches C．will study, will catch D．studies, will catch 18．I don't know if it _________ tomorrow. If it _________, we will stay at home together. A．snows; snows B．will snow; snow