Unit 8语法精讲精练原因状语从句2025-2026学年沪教版八年级英语下册

新沪教牛津八下英语 · U8语法精讲精练 Unit 8 Imagine that! · 原因状语从句（学生版） ( 囚 语法精讲 · 原因状语从句 ) ą 定义 原因状语从句用于说明主句动作发生的原因，由从属连词引导，不能独立成句，必须依附主句。 本单元重点连词：because 、as 、since 、for，另有短语类原因标志： because of。 㐱 引导词详解 引导词 含义 语气 用法特点 常用 位置 because 因为 ☆ 最强 表示直接、根本的原因，常用来回答 why 提问；强调原因从句时只能用 because 句首 / 句末 as 因为； 由于 ☆ 较弱 语气较弱，所表达的原因比较明显，口语中常用；不用于回答 why 问句 多放句首 since 既然 ☆ 较弱 表示已知的或对方已了解的原因，相当于“ 既然” ；常放句首 多放句首 for 因为 ☆ 最弱 表示推断或补充解释，不可放句首，前面通常有逗号；不能回答 why 问句 只能后置 㐱 because 与 because of 的区别 because 是连词，后接完整句子（主语 + 谓语）。 because of 是短语介词，后接名词、名词短语或代词（宾格）。转换规则：Because + 完整句子 ⇔ Because of + 名词/名词短语 例：Because it rained heavily, we stayed at home. = Because of the heavy rain, we stayed at home. 㐱 从句位置与标点规则 原因状语从句可放在主句前或主句后。 从句在前：连词 + 从句 ， + 主句。 （句首从句末尾必须加逗号） 从句在后：主句 + 连词 + 从句。 （句末从句前一般不加逗号） 例：Because he was scared, he ran away. / He ran away because he was scared. ( q 易错提醒： because 后接句子， because of 后接名词 / 名词短语。 误： because ofit rained x 正： because it rained ✅ / because of the rain ✅ ) ( 會 分层精练 ) Part A：单项选择（本大题共15小题，每小题2分，共30分） 1. We must protect the rainforests they are home to many rare animals. A. or B. because C. but D. so 2. everyone is here, let's begin the meeting. A. Although B. Because C. Since D. Unless 3. — Why didn't you go to the cinema with us? — ______ I had to finish my homework. A. As B. Since C. For D. Because 4. The ground is wet, it rained heavily last night. A. because B. for C. since D. as 5. you are tired, you can have a good rest. A. As B. Though C. If D. Unless 6. We had to stay at home all day the heavy rain. A. because B. since C. because of D. as 7. it was getting dark, we had to stop working. A. Since B. Because C. As D. All of the above 8. I didn't buy the jacket it was too expensive. A. so B. but C. because D. although 9. you have finished your work, you can leave now. A. Since B. Unless C. Although D. While 10. The match was cancelled the heavy rain. A. because B. because of C. since D. as 11. I like this school the teachers are very kind and helpful. A. though B. if C. because D. while 12. — She may need some help she is new here. — Let's help her as much as possible. A. though B. unless C. while D. as 13. you like reading, you can take this book home. A. Because B. Since C. As D. All of the above 14. He didn't pass the exam, he didn't study hard. A. for B. because C. since D. as 15. The spaceship couldn't fly the damage. A. because B. because of C. since D. as Part B：用所给连词填空（本大题共10小题，每小题2分，共20分） （because / as / since / for / because of） 16. you are already here, let's start the experiment. 17. He didn't go to school he had a fever. 18. it is raining outside, we have to cancel the picnic. 19. The ground is wet, it rained last night. 20. We put off the plan the bad weather. 21. everyone is here, let's take a group photo. 22. I was late for school I missed the first bus. 23. you don't know the truth, I will tell you. 24. The match was cancelled the heavy rain. 25. He stayed at home he was ill. ( 共 30 分） )Part C：完成句子（本大题共10小题，每小题3分， 26. 因为他们很专业而且总是鼓励我们，我们都很喜欢他们。 they are very and always us, we all like them. 27. 我经常去艺术馆，因为我喜欢绘画。 I often go to the art museum I like . 28. 既然你是个成年人了，你不应该再向父母要钱。 ______ you are an ______, you should not ask your parents for money. 29. 这些工人不得不停止工作，因为雨太大了。 （用 because of 改写） These workers had to stop working the rain. 30. 约翰想看访谈节目，因为它们令人愉快。 John wants to watch shows they are . 31. 艾米想要保留她的旧东西，因为它们唤起甜蜜的回忆。 Amy wants to keep her old things they sweet memories. 32. 我真的很累，因为我昨晚学习到午夜。 I'm really tired I until last night. 33. 卡尔森没有来参加聚会，因为他很忙。 Carlson didn't come to the party he was . 34. 既然这个项目很有价值，为何不尽快开展呢？ Why don't you start it it is of great ? 35. 我喜欢猫，因为它们很可爱。 I like cats they are . ( 共 20 分） )Part D：句型转换（本大题共5小题，每小题4分， 36. Because it snowed heavily, we stayed at home. （改为同义句） the heavy snow, we stayed at home. 37. He didn't come to the party. He was busy.（合并为一句） He didn't come to the party he was busy. 38. I like dogs. They are friendly.（合并为一句） I like dogs they are friendly. 39. She was late because she missed the bus. （对划线部分提问） she late? 40. Since you are here, let's start the meeting. （改为同义句） you are here, let's start the meeting. 㐱 参考答案 Part A：单项选择 1. B 2. C 3. D 4. B 5. A 6. C 7. D 8. C 9. A 10. B 11. C 12. D 13. D 14. A 15. B Part B：用所给词填空 16. Since 17. because 18. As / Because 19. for 20. because of 21. Since / As 22. because 23. Since / As 24. because of 25. because Part C：完成句子 26. Because; professional; encouraging 27. because; painting 28. Since; adult 29. because of; heavy 30. talk; because; enjoyable 31. because; bring 32. because; studied; midnight 33. because; busy 34. since; value 35. because; cute Part D：句型转换 36. Because of 37. because 38. because 39. Why was 40. As 学科网（北京）股份有限公司 $