Unit7语法讲解及习题：条件句（Conditional sentences）与 unless 2025-2026学年沪教版英语八年级上册

沪教（牛津）英语八上Unit7语法讲解及习题 条件句（Conditional sentences）与 unless 一、核心语法点 1. 零条件句（Conditional sentences for certain results） 含义：表示客观真理、自然规律、必然结果，只要条件满足，结果一定发生。 结构：If + 一般现在时，主句 + 一般现在时 例句： If you mix blue and yellow, you get green. 注意：主句和从句都不用将来时；主语是三单时，动词用三单形式。 2. 第一条件句（Possible future results） 含义：表示将来可能发生的事情及其结果。 结构：If + 一般现在时，主句 + will + 动词原形 例句： If it rains tomorrow, we will stay at home. 注意：if 从句不用 will，用一般现在时表将来。 3. unless 用法 含义：unless = if…not，意为“除非；如果不”。 结构：Unless + 一般现在时，主句 + will… 用法：引导否定条件，用于同义句改写。 例句： Unless you study hard, you won’t pass the exam. = If you don’t study hard, you won’t pass the exam. 注意：unless 从句不用将来时，用一般现在时表将来。 二、语法习题 题型一：匹配题 Read these if-clauses and match them with the results. 1. If you take a fish out of water, ______ 2. If you switch off the lamp, ______ 3. If you put wood into water, ______ 4. If you water a plant, ______ 5. If you drop a glass, ______ a. it grows. b. it dies. c. the room becomes dark. d. it breaks. e. it floats. 题型二：句型转换（用 unless 改写句子 ） 1. If it doesn’t rain, I’ll go for a picnic with my friends on Saturday. → _____________________________________________________ 2. I’m going to make a birthday card for my mother if I don’t have any better ideas. → _____________________________________________________ 3. I’ll finish reading Romance of the Three Kingdoms if I’m not too tired on Saturday evening. → _____________________________________________________ 4. I’ll help Su Mei practise English if my mother’s birthday party doesn’t end too late. → _____________________________________________________ 题型三：单项选择 1. If you mix red and white, you ______ pink. A. get B. will get C. got D. getting 2. If you ______ salt into water, it disappears. A. put B. will put C. puts D. putting 3. Unless you ______ enough sleep, you will not remember things well. A. get B. will get C. got D. getting 4. If you take a fish out of water, it ______. A. die B. dies C. will die D. died 5. If you switch off the lamp, the room ______ dark. A. becomes B. will become C. became D. becoming 6. Unless you ______ hard, you will not pass the exam. A. study B. will study C. studied D. studying 7. If you put wood into water, it ______. A. float B. floats C. will float D. floated 8. If you water a plant, it ______. A. grow B. grows C. will grow D. grew 9. If you drop a glass, it ______. A. break B. breaks C. will break D. broke 10. I’ll go for a picnic with my friends on Saturday ______ it doesn’t rain. A. if B. unless C. when D. because 11. I’m going to make a birthday card for my mother ______ I have any better ideas. A. if B. unless C. when D. because 12. I’ll finish reading Romance of the Three Kingdoms ______ I’m too tired on Saturday evening. A. if B. unless C. when D. because 13. I’ll help Su Mei practise English ______ my mother’s birthday party ends too late. A. if B. unless C. when D. because 14. If you put some ice into a cup of hot water, it ______. A. melt B. melts C. will melt D. melted 15. What do dogs do if a stranger ______ close? A. come B. comes C. will come D. came 题型四：用所给动词的适当形式填空 1. If you mix blue and yellow, you ______________ (get) green. 2. If you put salt into water, it ______________ (disappear). 3. Unless you ______________ (get) enough sleep, you will not remember things well. 4. If you take a fish out of water, it ______________ (die). 5. If you switch off the lamp, the room ______________ (become) dark. 6. Unless you ______________ (study) hard, you will not pass the exam. 7. If you put wood into water, it ______________ (float). 8. If you water a plant, it ______________ (grow). 9. If you drop a glass, it ______________ (break). 10. If you put some ice into a cup of hot water, it ______________ (melt). 11. What do dogs do if a stranger ______________ (come) close? 三、答案与详细解析 题型一：匹配题 1. b 解析：零条件句，自然规律。 2. c 解析：零条件句，必然结果。 3. e 解析：零条件句，物理常识。 4. a 解析：零条件句，自然规律。 5. d 解析：零条件句，必然结果。 题型二：句型转换 1. Unless it rains, I’ll go for a picnic with my friends on Saturday. 解析：unless = if…not，从句用一般现在时。 2. Unless I have any better ideas, I’m going to make a birthday card for my mother. 解析：if…not = unless，注意时态不变。 3. Unless I’m too tired on Saturday evening, I’ll finish reading Romance of the Three Kingdoms. 解析：if not = unless。 4. Unless my mother’s birthday party ends too late, I’ll help Su Mei practise English. 解析：if…not 可替换为 unless。 题型三：单项选择 1. A 解析：零条件句，主从句都用一般现在时。 2. A 解析：零条件句，if 从句用一般现在时。 3. A 解析：unless 从句用一般现在时表将来。 4. B 解析：零条件句，主语 it 是三单，动词用三单形式。 5. A 解析：零条件句，主语 the room 是三单。 6. A 解析：unless 从句用一般现在时。 7. B 解析：零条件句，主语 it 是三单。 8. B 解析：零条件句，主语 it 是三单。 9. B 解析：零条件句，主语 it 是三单。 10. A 解析：if 表示“如果”，引导肯定条件。 11. B 解析：unless = if…not，意为“除非”。 12. B 解析：unless = if…not。 13. B 解析：unless = if…not。 14. B 解析：零条件句，主语 it 是三单。 15. B 解析：零条件句，主语 a stranger 是三单。 题型四：用所给动词的适当形式填空 1. get 解析：零条件句，用一般现在时。 2. disappears 解析：零条件句，主语 it 三单。 3. get 解析：unless 从句用一般现在时。 4. dies 解析：零条件句，主语 it 三单。 5. becomes 解析：零条件句，主语 the room 三单。 6. study 解析：unless 从句用一般现在时。 7. floats 解析：零条件句，主语 it 三单。 8. grows 解析：零条件句，主语 it 三单。 9. breaks 解析：零条件句，主语 it 三单。 10. melts 解析：零条件句，主语 it 三单。 11. comes 解析：零条件句，主语 a stranger 三单。 ( 1 ) 学科网（北京）股份有限公司 $