Unit5语法讲解及习题_原因状语从句（Adverbial clauses of reason）2026-2027学年沪教版英语八年级上册

该初中英语单元知识清单系统梳理了沪教牛津八上Unit5核心语法“原因状语从句”，涵盖because、as、since三大引导词的基础概念、用法解析及语法规则，搭建从“概念理解”到“引导词对比”再到“规则应用”的递进式学习支架。 清单通过“易混对比总结表”清晰呈现引导词语气、场景等差异，结合教材原句及团队合作主题设计实例，配套单选、选词填空等多样化题型，培养学生语言能力与思维品质。特别设置错题解析与翻译练习，助力学生自主学习，教师可据此实施针对性教学，提升课堂效率。

沪教牛津英语八上Unit5语法讲解及习题: 原因状语从句（Adverbial clauses of reason） 一、单元核心语法：原因状语从句（because /as/since） 本单元主题为Teamwork（团队合作），Grammar in use 板块核心语法是原因状语从句，用于回答 why 引导的问句，说明主句动作发生的原因，主要引导词：because、as、since。 （一）基础概念 原因状语从句用来交代主句事件发生的缘由，翻译为 “因为……”，三个引导词含义相近，但语气强弱、使用场景、句式位置有区别。 （二）三个引导词核心用法 + 教材原句解析 1. because（语气最强，最常用） · 侧重直接、客观、重要的原因，是回答 why 问句的唯一标准用词 · 可放主句前或主句后，放句首时需要逗号隔开 · 不能和 so 连用（英语连词二选一） 教材原句： Three boys were also unhappy because they got no parts to play but the job of helping out backstage with Shirley. 三个男孩也不开心，因为他们没有演出角色，只能在后台给 Shirley 帮忙。 例句（贴合 teamwork 话题）： The team won the competition because everyone tried their best. 这支队伍赢得比赛，因为所有人都全力以赴。 2. as（语气中等，多用于口语） · 原因是双方都已知的、显而易见的事实 · 通常放在句首，书面口语均可 教材原句： Sam pulled a long face as he felt the same way. 山姆耷拉着脸，因为他也有同样的感受。 例句： As we have good teamwork, we can finish the task quickly. 因为我们配合默契，能快速完成任务。 3. since（语气最弱，正式书面语） · 译为 “既然”，原因是说话双方心知肚明的前提 · 大多置于句首 教材原句： Since Ella always seemed self-important, Shirley had never liked her. 既然 Ella 总是显得自负，Shirley 一直都不喜欢她。 例句： Since you are good at planning, you can be our team leader. 既然你擅长制定计划，你可以担任我们的队长。 （三）核心语法规则 1. 禁止搭配：because/since/as 不能和 so 连用 ✅ He joined the robot club because he loved machines. ❌ He joined the robot club because so he loved machines. 2. 句式位置 · 从句前置：引导词 + 从句，主句（加逗号） Since everyone supports each other, the team works well. · 从句后置：主句 + 引导词 + 从句（不加逗号） The team works well since everyone supports each other. 3. 三者语气排序：because > as > since （四）易混对比总结 引导词 语气 使用场景 能否回答why提问 常用位置 because 最强 直接客观原因 ✅ 可以 句首 / 句末 as 中等 已知事实，口语 ❌ 不用于答 why 多句首 since 最弱 既然，显而易见的前提 ❌ 不用于答 why 句首 二、专项练习题 题型一：单项选择 1. The group finished the project ahead of time__________ they helped one another. A. so B. because C. but D. though 2. __________ you know much about designing, you can take charge of this part of the task. A. Since B. Because C. So D. Though 3. He didn’t join the basketball club__________ he was too busy with his group task. A. so B. for C. because D. though 4. As all members trusted each other,__________ they solved the problem easily. A. so B. / C. but D. and 5. —Why did your team get first prize? —__________ we had a clear plan before we started working. A. Since B. As C. Because D. For 6. The boy refused to argue__________ he did not want to break the team harmony. A. as B. since C. because D. though 7. __________ the task was difficult, they kept trying together and succeeded at last. A. Because B. Since C. As D. All above 8. She was chosen as team leader__________ she was responsible and careful. A. so B. because C. but D. though 9. __________ you have lots of creative ideas, the robot club will welcome you. A. Since B. Because C. If D. When 10. We respect our teammates__________ everyone has different strengths. A. because B. so C. though D. but 题型二：用 because/as/since 选词填空 1. ______________ it is a team game, no one can win the match alone. 2. The student left the debate club______________ he had too much homework every Friday. 3. ______________ you are free this afternoon, why not join our group discussion? 4. Our team failed the game______________ some members did not take it seriously. 5. ______________ the plan has been agreed by everyone, we can start our work now. 6. I want to join the robot club______________ I am interested in making small machines. 7. He kept silent______________ he knew his words would make his teammates upset. 8. ______________ you have experience in teamwork, you can give us some advice. 9. They set up small groups______________ it was easier to divide different jobs. 10. The teacher praised the whole class______________ they finished the group project perfectly. 题型三：改错（划出错误并改正 ） 1. Because they practiced every day, so their team became stronger and stronger. 2. Since he was good at organizing activities, so we asked him to be our group leader. 3. As the task was hard, but all the members tried their best to finish it. 4. —Why didn’t you take part in the competition? —Since I hurt my arm last week. 5. Because everyone had clear jobs, so the teamwork went very smoothly. 题型四：合并句子（用 because/as/since 改写 ） 1. He joined the debating club. He likes expressing his own opinions. 2. You know a lot about teamwork. You can share your experience with us. 3. The team lost the match. They didn’t communicate well with each other. 4. We trust our teammates. We are willing to help each other when in trouble. 题型五：句子翻译（使用对应引导词） 1. 因为队员们互相支持，这支队伍克服了很多困难。（because） _____________________________________________________________________ 2. 既然你擅长策划活动，你可以负责这次团建任务。（since） _____________________________________________________________________ 3. 由于时间有限，我们分成小组来完成这项任务。（as） _____________________________________________________________________ 4. 他退出了机器人社团，因为他没有足够的课余时间。（because） _____________________________________________________________________ 三、参考答案 + 详细解析 题型一：单项选择 1. B 解析：because 引出团队互相帮助的原因 2. A 解析：since 表示 “既然”，双方都知道对方擅长设计 3. C 解析：because 回答客观原因，不能用 so 4. B 解析：as 和 so 不可连用，空格不填单词 5. C 解析：只有 because 可以回答 why 引导的问句 6. C 解析：because 强调不想破坏团队和谐的直接原因 7. D 解析：三个词在此句均可使用，表原因 8. B 解析：because 说明被选为队长的理由 9. A 解析：since “既然你富有创意” 10. A 解析：because 解释尊重队友的原因 答案：1.B 2.A 3.C 4.B 5.C 6.C 7.D 8.B 9.A 10.A 题型二：选词填空 1. Since 2. because 3. Since 4. because 5. As/Since 6. because 7. as 8. Since 9. because 10. because 题型三：改错 1. 去掉 so → Because they practiced every day, their team became stronger and stronger. 2. 去掉 so → Since he was good at organizing activities, we asked him to be our group leader. 3. 去掉 but → As the task was hard, all the members tried their best to finish it. 4. Since 改为 Because → Because I hurt my arm last week.（答 why 只能用 because） 5. 去掉 so → Because everyone had clear jobs, the teamwork went very smoothly. 题型四：合并句子 1. He joined the debating club because he likes expressing his own opinions. 2. Since you know a lot about teamwork, you can share your experience with us. 3. The team lost the match because they didn’t communicate well with each other. 4. As we trust our teammates, we are willing to help each other when in trouble. 题型五：句子翻译 1. The team got through many difficulties because the members supported each other. 2. Since you are good at planning activities, you can take charge of this team-building task. 3. As time was limited, we divided into small groups to finish the task. 4. He left the Robot Club because he didn’t have enough spare time. ( 1 ) 学科网（北京）股份有限公司 $