人教版八上If引导的条件状语从句知识点讲解与专项练习题（含答案）

If引导的条件状语从句知识点讲解与专项练习题 一、核心知识点讲解 1. 核心定义 if 表示“如果”，引导的条件状语从句用来表示“在某种条件下，某事才会发生”，从句在句中作状语，起修饰主句的作用。 2. 句子结构 结构一：if 从句 + 逗号 + 主句 例句：If you take the bus to the party, you’ll be late. 结构二：主句 + if 从句 例句：You’ll be late if you take the bus to the party. 3. 三大时态原则 这是 if 条件状语从句的核心考点，必须牢记“从句用现在时，主句用将来/情态/祈使形式” ①主将从现：主句用一般将来时（will + 动词原形），if 从句用一般现在时 例句：If I get up late tomorrow, I’ll be late for school. ②主情从现：主句含情态动词（must/can/may/should 等），if 从句用一般现在时 例句：If you have the flu, you should see a doctor. ③主祈从现：主句是祈使句，if 从句用一般现在时 例句：Let me know if you need my help. 4. 常见句型转换 ①if not 与 unless 互换：if not = unless（除非；如果不） 例句：If you don’t get up early, you’ll be late. = Unless you get up early, you’ll be late. ②祈使句+and/or+一般将来时 if 从句 顺承关系（and）：Study hard, and you’ll pass the exam. = If you study hard, you’ll pass the exam. 转折关系（or）：Study hard, or you won’t pass the exam. = If you don’t study hard, you won’t pass the exam. ③with/without 短语 if 从句 例句：If you help me, I’ll finish the work. = With your help, I’ll finish the work. 5. 特殊用法 ①if 条件状语从句中，用 any 代替 some 表示“一些” 例句：If you have any questions, ask the teacher. ②用助动词 do/does/did 替代前文重复的动作 例句：I think I’ll take the bus. If you do, you’ll be late. ③if 表“是否”时，引导的是宾语从句，时态根据语境变化，不遵循“主将从现” 例句：I want to know if he will come to the party. 二、专项练习题 （一）单项选择 If you _____ English every day, your English _____ better. A. learn; will get B. will learn; get C. learn; get D. will learn; will get —If she _____ to the party, she _____ a gift for us. —That’s great. A. comes; brings B. will come; will bring C. comes; will bring D. will come; brings We _____ a picnic if the weather _____ fine this Sunday. A. have; is B. will have; is C. have; will be D. will have; will be I don’t know if he _____ tomorrow. If he _____, I’ll call you at once. A. comes; comes B. will come; comes C. comes; will come D. will come; will come If you have _____ problems, don’t be afraid to ask for help. A. some B. any C. a D. an _____ you don’t wear a helmet, you may get hurt when riding a bike. A. If B. Unless C. Because D. So Let us know if you _____ the answer to this question. A. find B. finds C. will find D. found If it _____ snow next week, we _____ go skiing. A. snow; will B. snows; will C. will snow; / D. snowed; would —Can I use your computer —Yes, you can if you _____ it clean. A. keep B. will keep C. kept D. keeps If you _____ the book, you _____ the interesting stories in it. A. read; find B. will read; find C. read; will find D. read; finds If they _____ the project on time, they _____ a big prize. A. finish; get B. will finish; get C. finish; ... ...