Unit 5 语法讲解及习题：because for since as 表原因状语从句 2026-2027学年译林版九年级英语上册

译林英语九上Unit5语法讲解及习题： because / for / since / as 表原因状语从句 一、语法核心知识点详解 本单元语法核心是四个引导原因的连词：because、for、since、as，均用来解释事情发生的缘由，但语气强弱、使用场景、句子位置规则有明确区分，结合本单元音乐、音乐家话题讲解。 （一）because 1. 语气强度：四个词中语气最强，专门用来回答 Why 提出的问题。 2. 使用场景：引出听者未知、新出现的原因，是最直白客观的理由。 3. 位置规则：because 引导的从句可放在主句前，也可放在主句后；从句放句首时，主句前必须加逗号分隔。 4. 例句 · He loves Tan Dun’s works because they mix Chinese natural sounds and Western instruments.（从句后置） · Because his music carries Chinese culture, it wins high praise around the world.（从句前置，加逗号） 5. 关键考点：回答 why 问句，只能用 because，不能用 for/since/as。 —Why do you admire Tan Dun? —Because he creates music from the sounds of nature. （二）for 1. 语气强度：语气最弱，属于书面文学用词，不用于口语。 2. 使用场景：补充、推论性的理由，是事后追加说明，不解释直接因果。 3. 位置规则：只能放在主句之后，绝对不能置于句首；主句与 for 从句之间必须加逗号。 4. 例句 · We all enjoy his concert, for every piece tells a story of nature. · This CD sells well, for it includes music for the Beijing Olympics. 5. 易错提醒：for 不能用来回答 why 问句，不能单独成句。 （三）since 1. 语气强度：语气弱于 because，和 as 基本无差别。 2. 使用场景：引出双方都已知、显而易见的原因，理由无需额外解释。 3. 位置规则：从句可放句首或主句后；从句前置时，主句前加逗号。 4. 例句 · Since you like classical music, you can listen to Mozart’s pieces. · Tan uses water sounds a lot since he thinks nature has its own music. （四）as 1. 语气强度：和 since 完全对等，口语、书面均可使用。 2. 使用场景：同样引出众所周知、不用特意说明的原因。 3. 位置规则：同 since，句首、句中均可，前置需逗号。 4. 单元话题例句 · As the school will hold a music festival, many students are learning instruments. · We will invite a violinist as everyone loves violin music. （五）四词对比总结表 连词 语气 核心用法 位置限制 能否回答why because 最强 未知、直接因果，客观理由 主句前 / 后均可 ✅ 唯一可用 for 最弱 书面推论、补充说明 仅能主句后，逗号隔开 ❌ 不可以 since 中等偏弱 双方已知的事实理由 主句前 / 后均可 ❌ 不可以 as 中等偏弱 与 since 完全通用 主句前 / 后均可 ❌ 不可以 二、分层专项练习题 题型一：单项选择 1. —Why do you prefer pop music? —________it makes me relaxed after study. A. For B. Because C. Since D. As 2. Tan Dun’s music is famous all over the world, ________it brings together Eastern and Western music styles. A. because B. as C. for D. since 3. ________we all know that you play the piano well, you can join the festival show. A. Because B. For C. Since D. Why 4. We seldom buy this old record, ________its price is too high. A. for B. as C. since D. because 5. ________the concert starts at 6 p.m., we have to leave home early. A. For B. Because C. Since D. All above 6. You won’t find this song boring, ________it has beautiful natural sounds inside. A. because B. for C. as D. since 7. —Why does Sandy like light music? —________it helps her finish homework faster. A. As B. Since C. For D. Because 8. This composer is special ________he uses stones and paper to make music. A. for B. because C. as D. since 9. ________you don’t like loud rock music, let’s choose a soft piano piece. A. Since B. For C. Because D. A & C 均可 10. Nobody misses his performance, ________every note touches people’s hearts. A. because B. for C. as D. since 11. ________the students want to learn musical instruments, the school opens music lessons. A. For B. Since C. Why D. For that 12. We respect Tan Dun, ________he spreads Chinese music to the whole world. A. as B. for C. because D. since 题型二：选词填空 1. ________many people enjoy natural music, Tan’s works are always popular. 2. He keeps collecting old musical instruments, ________he hopes to make a music show. 3. —Why do you practise the guitar every day? —________I want to perform at the school music festival. 4. The band’s new album sells quickly, ________it mixes traditional Chinese erhu and Western guitar. 5. ________the music festival welcomes parents, we prepared many seats for them. 6. We listen to this piece again and again, ________it carries warm stories of our hometown. 题型三：句型转换 1. He writes lots of folk songs. He loves Chinese traditional culture.（because） 2. This song is great. It won many music prizes.（for） 3. You are good at singing. You can take part in the singing competition.（since） 4. The teacher plays Mozart’s music in class. It can calm students down.（as） 5. People praise this composer highly. He creates music from daily objects.（because） 6. We will design festival posters together. Drawing is our common hobby.（for） 题型四：单句改错 1. For he loves nature, Tan uses water sounds in his music. 错误：________改正：________ 2. —Why do you love classical music? —As it is full of power. 错误：________改正：________ 3. The piano lesson is popular because, many students want to learn to play. 错误：________改正：________ 4. Since the concert will be held tomorrow we need to prepare instruments. 错误：________改正：________ 5. We like this musician, because his songs always warm our hearts.（本句改用 for 改写，修改一处） 题型五：中英互译 1. As this piece of music uses bamboo sounds, it has strong Chinese style. 中文翻译：_____________________________________________________________________ 2. 我们都期待这场音乐会，因为它的作曲者是谭盾。（because） 英文翻译：_____________________________________________________________________ 3. He seldom listens to rock music, for it is too noisy for him. 中文翻译：_____________________________________________________________________ 4. 既然你擅长拉小提琴，你可以在音乐节上表演。（since） 英文翻译：_____________________________________________________________________ 三、习题答案 + 详细解析 题型一：单项选择 1. B 解析：回答 Why 问句，只能用 because。 2. C 解析：逗号分隔主句，后置补充推论理由，用 for。 3. C 解析：“我们都知道” 是双方已知事实，用 since。 4. D 解析：直接客观因果，从句后置用 because。 5. C 解析：已知客观事实，从句前置用 since；for 不能放句首，because 语气过重。 6. B 解析：主句后逗号分隔，补充推论，书面语境用 for。 7. D 解析：回答 Why 问句固定用 because。 8. B 解析：直接解释他特别的核心原因，用 because。 9. D 解析：since 和 as 都可引出已知理由，此处均可。 10. B 解析：主句后逗号，追加推论理由，书面用 for。 11. B 解析：从句前置，已知事实，用 since；for 不能放句首。 12. C 解析：解释尊重他的直接核心原因，用 because。 题型二：选词填空 1. Since / As 解析：从句前置，“很多人喜欢自然音乐” 是大众已知事实。 2. because 解析：直接解释收集乐器的目的因果。 3. Because 解析：回答 why 问句，固定搭配。 4. for 解析：主句后逗号，补充专辑热销的推论理由。 5. Since / As 解析：前置从句，“音乐节对家长开放” 是既定事实。 6. for 解析：主句后逗号，追加反复聆听的补充理由。 题型三：句型转换 1. He writes lots of folk songs because he loves Chinese traditional culture. 解析：because 从句后置，直接因果。 2. This song is great, for it won many music prizes. 解析：for 必须放主句后，加逗号分隔。 3. Since you are good at singing, you can take part in the singing competition. 解析：since 从句前置，主句前加逗号。 4. As the teacher plays Mozart’s music in class, it can calm students down. 解析：as 引导已知理由，从句前置加逗号。 5. People praise this composer highly because he creates music from daily objects. 解析：because 后置，解释赞美他的直接原因。 6. We will design festival posters together, for drawing is our common hobby. 解析：for 后置，逗号隔开，补充说明理由。 题型四：单句改错 1. 错误：For；改正：Since / As 解析：for 不能放在句子开头。 2. 错误：As；改正：Because 解析：回答 Why 问句只能用 because。 3. 错误：because,；改正：because 解析：because 从句后置时，不需要在 because 后加逗号。 4. 错误：tomorrow；改正：tomorrow, 解析：since 从句前置，主句前必须加逗号分隔。 5. 改写答案：We like this musician, for his songs always warm our hearts. 解析：for 后置，逗号隔开，替换 because。 题型五：中英互译（4 题） 1. 翻译：因为这首曲子融入了竹乐器的声响，带有浓厚的中国韵味。 2. 翻译：We all look forward to this concert because its composer is Tan Dun. 3. 翻译：他很少听摇滚乐，因为对他来说这种音乐太吵闹了。 4. 翻译：Since you are good at playing the violin, you can perform at the music festival. ( 1 ) 学科网（北京）股份有限公司 $