Unit 5 Play by the rules语法精讲精练 2026-2027学年外研版英语八年级上册

该初中英语知识清单系统梳理了外研版八上Unit 5“动词不定式作目的状语”语法点，涵盖to do、in order to、so as to的用法及异同、否定形式、与目的状语从句的转换、目的与结果状语区分五大知识范畴，为学生搭建了从基础用法到句式转换再到易混点辨析的递进式学习支架。 清单通过对比表格呈现三种目的表达的位置差异，以“易错警示”突出“逻辑主语一致”“so as to不可位于句首”等重难点，典型例题精讲结合解析培养学生的语言能力和思维品质。分层练习设计满足不同学习需求，答案解析详细，助力学生自主巩固，也为教师提供精准教学支持。

外研版 八上 Unit 5 Play by the rules?语法精讲精练 —— 动词不定式作目的状语 —— 使用说明 动词不定式作目的状语，用来说明主语「为了什么」而做某个动作，是初中英语写作中表目的的核心手段，也是句型转换（简单句与目的状语从句互换）的高频考点。本讲系统讲解 to do、in order to、so as to 三种目的表达的位置与异同、否定目的的正确形式，以及与 so that/in order that 目的状语从句的转换，配套三类分层练习，答案与解析统一附于文末。 第一讲 知识精讲 一、to do 直接作目的状语 动词不定式可直接作目的状语，用来修饰动词，表示某一动作或状态的目的，相当于汉语的「为了……；来（去）做某事」，可译为「为了」。 Mum came back early to give me a surprise. 为了给我一个惊喜，妈妈很早就回来了。 My brother went to the library to borrow a dictionary. 为了借一本词典，我哥哥去了图书馆。 位置：句末或句首 目的状语可位于句末（最常见），也可提至句首表示强调；提至句首时常用逗号与主句隔开。 He got up early to catch the bus. 为了赶公交车，他起得很早。（句末） To catch the bus, he got up early. 为了赶公交车，他起得很早。（句首，逗号隔开） 【易错警示】逻辑主语要一致：不定式作目的状语时，其逻辑主语通常就是句子的主语。To learn English well, a dictionary is needed.（×，dictionary 不能 learn）应为 To learn English well, I need a dictionary.（√） 二、in order to / so as to 强调目的 为了使表达更清楚或对目的加以强调，可用 in order to do 或 so as to do，三者意义相同，可互换：to do = in order to do = so as to do。但它们在句中的位置不同： 目的表达 句末 句首 例句 to do 可以 可以 He works hard to succeed. / To succeed, he works hard. in order to do 可以 可以 In order to finish his work on time, he works very hard. = He works very hard in order to finish his work on time. so as to do 可以 不可以（不能位于句首） He trained hard so as to improve his basketball skills. 他努力训练以提高篮球技术。 【易错警示】so as to 只能放在句中（句末），不能提至句首；in order to 句首、句末均可。所以句首表目的只能用 To do 或 In order to do，不能用 *So as to do。 三、否定目的：in order not to / so as not to 表示「为了不……」这一否定目的时，不能直接用「not to do」，而要用 in order not to do 或 so as not to do（not 放在 to 前）。 正误 句子 说明 × 错误 I have to write it down not to forget. 不能直接用 not to do 表否定目的 √ 正确 I have to write it down in order not to forget. 为了不忘记，我得把它写下来。 √ 正确 She left quietly so as not to wake the baby. 她轻轻离开，以免吵醒宝宝。 【易错警示】否定词 not 紧跟在 in order / so as 之后、to 之前：in order not to do、so as not to do；普通 to do 的否定式 not to do 一般不作目的状语。 四、与 so that / in order that 目的状语从句的转换 to do / in order to / so as to 后接动词原形，构成简单句；so that / in order that 后接「主语 + can/could/will/would + 动词原形」的目的状语从句，构成复合句。当主从句主语一致时，两者可相互转换。 简单句（不定式） 复合句（目的状语从句） He got up early to/in order to/so as to catch the bus. He got up early so that/in order that he could catch the bus. She speaks slowly in order to be understood. She speaks slowly so that she can be understood. 【注】① so that 引导目的状语从句时，从句常含 can/could/may/might/will/would 等情态动词。② 只有主、从句主语一致时才能简化为不定式；主语不同则不能：He spoke loudly so that we could hear him.（不能简化为 *to hear him） 五、目的状语与结果状语的区分 only to do 表示「结果却……」，指出乎意料、往往令人失望的结果，不是目的，注意区分。 He hurried to the station only to find the train had left. 他匆忙赶到车站，结果却发现火车已经开走了。（结果，非目的） He hurried to the station to catch the train. 他匆忙赶到车站去赶火车。（目的） 六、典型例题精讲 【例1】Mum came back early ______ me a surprise. A. give B. to give C. giving D. gave 【答案】B 【解析】「早回来」的目的是「给我惊喜」，用不定式 to give 作目的状语，故选 B。 【例2】______ finish the task on time, he works very hard. A. So as to B. In order to C. So that D. In order that 【答案】B 【解析】空格位于句首且后接动词原形 finish，只能用 In order to；so as to 不能用于句首，so that/in order that 后接从句，故选 B。 【例3】I have to write it down ______ forget it. A. not to B. to not C. in order not to D. so as to not 【答案】C 【解析】否定目的用 in order not to / so as not to，not 位于 to 前，故选 C。 【例4】He got up early ______ he could catch the first bus. A. so as to B. in order to C. so that D. to 【答案】C 【解析】空格后是从句（he could catch...），用 so that/in order that 引导目的状语从句，故选 C。 【例5】He ran to the station, only ______ that the train had left. A. find B. to find C. finding D. found 【答案】B 【解析】only to do 表示出乎意料的结果「结果却发现」，用 to find，故选 B。 第二讲 综合演练 题型一 单项选择（每小题1分，共15分） 1. Mum came back early ______ me a surprise. A. give B. to give C. giving D. gave 2. ______ the early bus, he got up at five. A. Catch B. To catch C. Catching D. Caught 3. My brother went to the library ______ a dictionary. A. borrow B. to borrow C. borrowing D. borrowed 4. He trained hard ______ improve his basketball skills. A. so that B. in order that C. so as to D. because 5. ______ finish the work on time, we must work very hard. A. So as to B. In order to C. So that D. In order that 6. I have to write it down ______ forget it. A. not to B. to not C. in order not to D. so as to not 7. She got up early ______ she could catch the first bus. A. so as to B. in order to C. so that D. to 8. ______ late for the meeting, he took a taxi. A. Not be B. In order not to be C. So as to not be D. To not be 9. He ran to the station, only ______ the train had left. A. find B. to find C. finding D. found 10. We should eat more vegetables ______ healthy. A. keep B. to keep C. keeping D. kept 11. Which of the following sentences is RIGHT? A. So as to catch the bus, he ran fast. B. In order to catch the bus, he ran fast. C. He ran fast so that catch the bus. D. To not be late, he got up early. 12. He spoke in a loud voice ______ make himself heard. A. so that B. in order that C. in order to D. because of 13. He works day and night ______ he can support his big family. A. in order to B. so as to C. in order that D. to 14. She turned down the TV ______ wake the sleeping baby. A. in order to B. so as to C. in order not to D. not 15. ______ a good seat, she arrived at the theatre an hour early. A. In order that B. So as to C. In order to D. Because 题型二 用所给动词或短语的适当形式填空（每小题1分，共12分） 1. He got up early ______ (catch) the first bus. 2. ______ (keep) fit, she runs for half an hour every morning. 3. He spoke slowly in order ______ (make) himself understood. 4. She left quietly so as not ______ (wake) the sleeping baby. 5. We eat ______ (live), but we do not live ______ (eat). 6. I'll repeat the rule in order ______ (not make) any mistakes. 7. He went to the corner shop ______ (buy) some milk. 8. ______ (not miss) the last train, we set off before dark. 9. She studies very hard ______ (enter) a key senior high school. 10. Please speak louder so as ______ (make) everyone hear you. 11. They stopped at the gas station ______ (get) some fuel. 12. He took a map with him in order not ______ (get) lost. 题型三 完成句子 / 句型转换（每小题2分，共10题） A. 根据汉语意思完成句子（1—5题，每空一词） 1. 为了赶公交车，他起得很早。 ______ ______ the bus, he got up early. 2. 我哥哥去图书馆是为了借一本词典。 My brother went to the library ______ ______ a dictionary. 3. 为了按时完成工作，他非常努力。 ______ ______ ______ finish his work on time, he works very hard. 4. 为了不忘记，我不得不把它写下来。 I have to write it down ______ ______ ______ ______ forget. 5. 他刻苦训练以提高自己的篮球技术。 He trained hard ______ ______ improve his basketball skills. B. 句型转换（6—10题，每空一词） 6. He got up early so that he could catch the first bus.（用 in order to 改为简单句） He got up early ______ ______ ______ the first bus. 7. To learn English well, she reads aloud every morning.（用 so that 改为复合句） She reads aloud every morning ______ ______ she ______ learn English well. 8. He ran fast so as to catch up with me.（用 so that 改为复合句） He ran fast ______ ______ he ______ catch up with me. 9. In order not to be late, she took a taxi.（用 so that 改为复合句） She took a taxi ______ ______ she ______ ______ late. 10. He works hard. He wants to pass the coming exam.（用 in order to 合并为一句） He works hard ______ ______ ______ pass the coming exam. 答案与解析 题型一 单项选择 1. 【答案】B 【解析】to give 作目的状语，表「为了给我惊喜」 2. 【答案】B 【解析】句首目的状语 To catch，逗号隔开 3. 【答案】B 【解析】to borrow 作 went 的目的状语 4. 【答案】C 【解析】后接动词原形 improve，用 so as to；so that/in order that 接从句 5. 【答案】B 【解析】句首且接动词原形，只能 In order to 6. 【答案】C 【解析】否定目的 in order not to 7. 【答案】C 【解析】后接从句 she could...，用 so that 8. 【答案】B 【解析】否定目的且位于句首，In order not to be 9. 【答案】B 【解析】only to do 表出乎意料的结果 10. 【答案】B 【解析】to keep healthy 表目的 11. 【答案】B 【解析】so as to 不能句首（A错）；so that 后接从句（C错）；否定目的不能 to not（D错） 12. 【答案】C 【解析】后接动词原形 make，用 in order to 13. 【答案】C 【解析】后接从句 he can...，用 in order that 14. 【答案】C 【解析】调小电视是为了不吵醒宝宝，in order not to 15. 【答案】C 【解析】句首接动词原形 get，用 In order to 题型二 适当形式填空 1. 【答案】to catch 【解析】to do 作目的状语 2. 【答案】To keep 【解析】句首目的，To keep，首字母大写 3. 【答案】to make 【解析】in order to do，to + 动词原形 4. 【答案】to wake 【解析】so as not to do，not 后接 to wake 5. 【答案】to live; to eat 【解析】「吃是为了活着，活着不是为了吃」，均为目的状语 6. 【答案】not to make 【解析】in order not to do 否定目的 7. 【答案】to buy 【解析】to do 作 went 的目的 8. 【答案】In order not to miss 【解析】句首否定目的，只能 In order not to，首字母大写 9. 【答案】to enter 【解析】to do 作 studies hard 的目的 10. 【答案】to make 【解析】so as to do 11. 【答案】to get 【解析】to do 作 stopped 的目的 12. 【答案】to get 【解析】in order not to do，not to get lost 以免迷路 题型三 完成句子 / 句型转换 1. 【答案】To catch 【解析】句首目的 To catch，首字母大写 2. 【答案】to borrow 【解析】to do 作目的状语 3. 【答案】In order to 【解析】句首强调目的，In order to，首字母大写 4. 【答案】in order not to 【解析】否定目的，in order not to 5. 【答案】so as to / in order to 【解析】句中表目的，so as to / in order to 均可 6. 【答案】in order to 【解析】so that 从句简化为 in order to + 动词原形 7. 【答案】so that; can 【解析】不定式转为 so that 目的从句，补情态动词 can 8. 【答案】so that; could 【解析】so as to do 转为 so that + 主语 + could do 9. 【答案】so that; wouldn't be 【解析】否定目的转为 so that...wouldn't be late 10. 【答案】in order to 【解析】两句合并，wants to pass 转为 in order to pass 学科网（北京）股份有限公司 $