Unit 4 School days时间介词&频度副词（核心语法精练）英语新教材译林版七年级上册

**基本信息** 聚焦时间介词（on/in/at）和频度副词核心语法，构建“概念-规则-应用”三阶训练体系，强化语言运用与逻辑思维。 **专项设计** |模块|题量/典例|方法提炼|知识逻辑| |----|-----------|----------|----------| |知识回顾|2类语法表格|时间介词按“具体日期/年季月/时刻”分类，频度副词按“频率高低+句中位置”排序|从概念定义到规则辨析（如节日持续时间用at），构建语法认知框架| |考点夯基|单选20题+填空20题+句型转换10题+翻译5题|单项选择考基础用法，填空练精准应用，句型转换强化否定/提问逻辑|由基础辨析到句式转换，提升语言理解与表达能力| |综合提升|短文选词5空+语法填空10空|短文选词考语境频率判断，语法填空融合介词与副词综合运用|从单句到语篇，培养逻辑分析与跨情境迁移能力|

Unit 4 School days核心语法精练·解析版 （时间介词 & 频度副词） 目录 二、考点夯基 3 一、单项选择 3 二、用正确的时间介词或频度副词填空 6 三、句型转换 8 四、翻译句子 10 1 一、短文选词填空 11 二、语法填空 12 一、表示时间的介词on/in/at 介词 用法 示例 on 用在表示具体的日期、星期几、特定的节日(一天)、具体某一天的上午、下午或晚上前。 on October 1st on Friday on Children’s Day on Monday morning in 用于年、季节、月份前,也可以泛指在上午、下午或晚上。 in 2020 in winter in March in the afternoon at 用于表示具体时刻、年龄或noon、 night等前。 at 8:00 at six(years old)/at the age of six at noon 注意： (1)如果节日不止一天,而是持续一段时间,介词应用at。如at the Spring Festival "在春节(期间)"。 (2)时间状语前不用介词的两种情况： 1　 当时间状语中含有this、 that、 these、 those、 last、 next、 every、 each等修饰语时; 2　 当时间状语是today、 tonight(今晚)、 tomorrow morning/afternoon/evening等时。 例句： 1　 I go to school on foot every morning. 我每天早上步行去上学。 2　 I’m at home tonight. 我今晚在家。 二、频度副词 基本概念 常考的频度副词（频率由低到高） 表示动作发生的频率常用频度副词 1. 常考的频度副词 频度副词 用法 never 意为"从不",表示否定意义。 seldom 意为"很少,不常",表示否定意义。 sometimes 意为"有时",表示动作时有发生,间隔较长。 often 意为"经常,时常",表示动作或状态的反复,中间有间断。 usually 意为"通常",表示习惯性动作或状态,很少有例外。 always 意为"总是,一直",表示的频率是最高的,表示动作反复发生。 2. 频度副词在句中的位置 位置 例句 频度副词+行为动词 We often play basketball after school. 放学后我们经常打篮球。 be动词、助动词、情态动词+频度副词 He is never late for school. 他上学从不迟到。 She can sometimes win a match. 她有时能赢得比赛。 We do not usually go swimming. 我们不经常去游泳。 注意： 1　 有时为了表示强调,会把sometimes、 usually、 always、 often等频度副词放在句首; 2　 还会把often放在句末,这时可用very或quite来修饰often。 例句： 1　 Sometimes my mum goes to work on foot. 有时我妈妈步行去上班。 2　 I like playing computer games, but my dad doesn’t let me play them very often. 我喜欢玩电脑游戏,但是我爸爸不让我经常玩。 3. 对频度副词进行提问 提问词 例句 how often He seldom does morning exercises. 他很少做早操。（对划线部分进行提问） → How often does he do morning exercises? 他多久做一次早操? 一、单项选择。 1. I go to school ______ 7:00 every morning. A. in B. on C. at D. for 【答案】C 【解析】at 用于具体时刻 7:00 前。句意：我每天早上七点去上学。 2. We have PE lessons ______ Monday afternoon. A. in B. on C. at D. of 【答案】B 【解析】Monday afternoon 是具体某一天的下午，用介词 on。句意：我们周一下午上体育课。 3. He ______ late for school. A. is never B. never is C. never does D. does never 【答案】A 【解析】频度副词放在 be 动词后；主语 he 搭配 is，never 置于 is 后面。句意：他上学从不迟到。 4. ______ do you play football? —Sometimes. A. How long B. How often C. How far D. How many 【答案】B 【解析】答句 Sometimes 表频率，对频率提问用 How often；How long 问时长，How far 问距离，How many 问数量。句意：—— 你多久踢一次足球？—— 有时候踢。 5. They go to the park ______ weekends. A. in B. on C. at D. of 【答案】C 【解析】固定搭配 at weekends 在周末。句意：他们周末去公园。 6. She ______ watches TV in the evening. A. often is B. is often C. often does D. often 【答案】D 【解析】句子已有实义动词 watches，不需要 be 动词 / 助动词，频度副词 often 放在实义动词前。句意：她晚上经常看电视。 7. We have no classes ______ last Friday. A. in B. on C. at D. / 【答案】/（不填） 【解析】时间词带有 last，前面不加任何时间介词。句意：上周五我们没有课。 8. He ______ plays computer games, so he is good at study. A. always B. usually C. seldom D. often 【答案】C 【解析】后半句 “他学习很好” 说明很少玩电脑游戏；seldom 很少，always 总是，usually 通常，often 经常。句意：他很少玩电脑游戏，所以学习很好。 9. Children like playing ______ summer. A. in B. on C. at D. for 【答案】A 【解析】in 用于季节 summer 前面。句意：孩子们喜欢在夏天玩耍。 10. I ______ walk to school, but sometimes I ride a bike. A. never B. usually C. seldom D. ever 【答案】B 【解析】后半句 “但有时候骑车” 说明通常步行；usually 通常，never 从不，seldom 很少。句意：我通常步行去上学，但有时候骑自行车。 11. The meeting is ______ the morning of September 10th. A. in B. on C. at D. for 【答案】B 【解析】the morning of September 10th 是特指具体某一天的上午，用 on。句意：会议在 9 月 10 日上午举行。 12. They ______ late. They are hard-working. A. are never B. never are C. always are D. are always 【答案】A 【解析】后一句 “他们很勤奋” 说明从不迟到；频度副词置于 be 动词 are 后。句意：他们从不迟到，学习很刻苦。 13. ______ I get up late on Sundays. A. Seldom B. Sometimes C. Always D. Usually 【答案】B 【解析】sometimes 可放在句首表强调；seldom/always/usually 一般不直接放句首。句意：周日我有时候起床很晚。 14. He doesn’t ______ eat snacks between meals. A. never B. seldom C. often D. always not 【答案】C 【解析】doesn’t 为否定助动词，后接 often；never、seldom 本身表否定，不能和 doesn’t 连用。句意：两餐之间他不常吃零食。 15. We have lunch ______ noon at school. A. in B. on C. at D. for 【答案】C 【解析】固定搭配 at noon 在中午。句意：我们中午在学校吃午饭。 16. She ______ her homework after school every day. A. always do B. always does C. does always D. do always 【答案】B 【解析】主语 she 三单，实义动词用 does；频度副词 always 放在实义动词前。句意：她每天放学后总会写作业。 17. I go swimming ______ every summer. A. in B. on C. at D. / 【答案】D 【解析】时间词带有 every，前面不加介词。句意：我每年夏天都去游泳。 18. He ______ tells lies, so we all trust him. A. always B. usually C. seldom D. never 【答案】D 【解析】后半句 “我们都信任他” 说明他从不说谎；never 从不。句意：他从不说谎，所以我们都信任他。 19. How often ______ you ______ basketball? A. do; play B. does; play C. do; plays D. does; plays 【答案】A 【解析】主语 you 是第二人称，助动词用 do；助动词后实义动词还原原形 play。句意：你多久打一次篮球？ 20. They ______ busy on weekdays. A. often are B. are often C. often do D. do often 【答案】B 【解析】busy 是形容词，前面用 be 动词 are；频度副词 often 放在 be 动词后。句意：工作日他们通常很忙。 二、用正确的时间介词或频度副词填空 1. We have lessons ______ the morning. 【答案】in 【解析】in 用于泛指的 in the morning 在上午。句意：我们上午上课。 2. Our lessons begin ______ 8:15 a.m. 【答案】at 【解析】at 用于具体时刻 8:15 a.m. 前。句意：我们八点十五开始上课。 3. I go to school ______ Monday. 【答案】on 【解析】on 用于星期 Monday 前面。句意：我周一去上学。 4. He plays football ______ Saturday afternoon. 【答案】on 【解析】Saturday afternoon 是具体某一天下午，用 on。句意：他周六下午踢足球。 5. They go out ______ weekends. 【答案】at 【解析】固定搭配 at weekends 在周末。句意：他们周末外出。 6. I get up early ______ every morning. 【答案】/（不填） 【解析】every 修饰 morning，前面不加介词。句意：我每天早上早起。 7. She is busy ______ winter. 【答案】in 【解析】in 用于季节 winter 前。句意：她冬天很忙。 8. We have no classes ______ Sunday. 【答案】on 【解析】on 用于星期 Sunday 前。句意：我们周日不上课。 9. He is______ (从不) late for school. 【答案】never 【解析】中文提示 “从不”，频度副词 never 放在 be 动词 is 后。句意：他上学从不迟到。 10. I ______ (通常) walk to school. 【答案】usually 【解析】中文提示 “通常”，放在实义动词 walk 前。句意：我通常步行去上学。 11. They ______ (经常) do their homework after school. 【答案】often 【解析】中文提示 “经常”，放在实义动词 do 前。句意：他们经常放学后写作业。 12. She ______ (很少) watches TV at night. 【答案】seldom 【解析】中文提示 “很少”，放在实义动词 watches 前。句意：她晚上很少看电视。 13. ______ (有时) I play basketball with my friends. 【答案】Sometimes 【解析】中文提示 “有时”，放句首首字母大写。句意：有时候我和朋友打篮球。 14. My mother ______ (总是) cooks dinner for me. 【答案】always 【解析】中文提示 “总是”，放在实义动词 cooks 前。句意：妈妈总是给我做晚饭。 15. We have a party ______ the afternoon of October 1st. 【答案】on 【解析】the afternoon of October 1st 特指某天下午，用 on。句意：我们 10 月 1 日下午举办派对。 16. He meets his friends ______ lunchtime. 【答案】at 【解析】固定搭配 at lunchtime 在午餐时间。句意：他午餐时间和朋友见面。 17. I go to the park ______ last Sunday.（不填/填介词） 【答案】/（不填） 【解析】last 修饰 Sunday，不加介词。句意：上周日我去了公园。 18. They will have a trip ______ next week.（不填/填介词） 【答案】/（不填） 【解析】next 修饰 week，不加介词。句意：他们下周要去旅行。 19. Cats sleep ______ the day and hunt ______ night. 【答案】in；at 【解析】in the day 在白天；at night 在夜晚，固定搭配。句意：猫白天睡觉，夜里捕猎。 20. I ______ am late for class. (never) 【答案】never 【解析】频度副词置于 be 动词 am 后。句意：我上课从不迟到。 三、句型转换 1. He is always busy on weekdays.（改为否定句） He ______ ______ busy on weekdays. 【答案】is never 【解析】原句含 be 动词 is，变否定直接用 never 放在 is 后。原句句意：他工作日总是很忙。改写句意：他工作日从不忙。 2. I usually go to school on foot.（对划线部分提问） ______ ______ ______ ______ ______to school on foot? 【答案】How often do you go 【解析】划线 usually 是频度副词，提问用 How often；主语 you，助动词 do，动词还原 go。原句句意：我通常步行上学。改写句意：你多久步行一次去上学？ 3. They often play football after school.（改为一般疑问句） ______ they ______ ______ football after school? 【答案】Do; often play 【解析】主语 they 复数，句首加助动词 Do；often 放实义动词 play 前。原句句意：他们放学后经常踢足球。改写句意：他们放学后经常踢足球吗？ 4. She seldom watches TV at night.（改为同义句） She ______ ______ watch TV at night. 【答案】don’t often 【解析】seldom 很少 = don’t often 不常；主语 she 三单，助动词用 doesn’t。原句句意：她晚上很少看电视。改写句意：她晚上不常看电视。 5. We have lessons in the morning.（改否定句） We ______ ______ lessons in the morning. 【答案】don’t have 【解析】主语 we 复数，实义动词 have 变否定加 don’t，动词用原形。原句句意：我们上午上课。改写句意：我们上午不上课。 6. Sometimes I walk home.（改为同义句） I ______ walk home. 【答案】sometimes 【解析】sometimes 可放句首或实义动词前，句中放 walk 前。原句句意：有时候我走路回家。改写句意：我有时候走路回家。 7. She is often late for school.（改否定句） She ______ ______ late for school. 【答案】isn’t often 【解析】be 动词 is 变否定 isn’t，频度副词 often 放在后面。原句句意：她上学经常迟到。改写句意：她上学不常迟到。 8. He always does his homework carefully.（改否定句） He ______ ______ his homework carefully. 【答案】never does 【解析】主语 he 三单，实义动词 does，never 放在 does 前。原句句意：他总是认真写作业。改写句意：他从不认真写作业。 9. They sometimes go shopping on Sunday.（对划线提问） ______ ______ ______ go shopping on Sunday? 【答案】How often do they 【解析】sometimes 表频率，用 How often 提问；主语 they，助动词 do。原句句意：他们周日有时候去购物。改写句意：他们多久在周日购物一次？ 10. Millie often reads books in the library.（用never改写句子） Millie ______ ______ books in the library. 【答案】never reads 【解析】主语 Millie 三单，never 放在实义动词 reads 前。原句句意：米莉经常在图书馆看书。改写句意：米莉从不在图书馆看书。 四、翻译句子 1. 我通常晚上九点上床睡觉。 ____________________________________________________ 【答案】I usually go to bed at nine o’clock in the evening. 【解析】usually 放在实义动词 go 前；时刻前用 at，泛指晚上用 in the evening。 2. 她工作日很少去电影院。 ____________________________________________________ 【答案】She seldom goes to the cinema on weekdays. 【解析】seldom 放实义动词前；on weekdays 在工作日。 3. 他上学从不迟到。 ____________________________________________________ 【答案】He is never late for school. 【解析】never 放在 be 动词 is 后；固定搭配 be late for school 上学迟到。 4. 我们有时候下课后打排球。 ____________________________________________________ 【答案】Sometimes we play volleyball after class. 【解析】sometimes 放句首表强调；after class 下课后。 5. 我的妈妈几乎不在空闲时间看卡通片。 ____________________________________________________ 【答案】My mother seldom watches cartoons in her free time. 【解析】seldom 放实义动词前；in free time 在空闲时间。 一、短文选词填空 always, usually, sometimes, seldom, never My name is Kitty, a Grade 7 student. I ____1____ get up at 6:40 a.m. on school days. I ____2____ miss morning reading. My mum ____3____ cooks noodles for breakfast, but ____4____ she makes bread. I ____5____ eat hamburgers because they are bad for my health. 【答案】 1. usually 2. never 3. usually 4. sometimes 5. never 【解析】 1. 【答案】usually 【解析】描述上学日常作息，通常 6:40 起床。句意：上学日我通常早上 6:40 起床。 2. 【答案】never 【解析】从不错过早读，符合好学生设定。句意：我从不错过早读。 3. 【答案】usually 【解析】妈妈早餐通常煮面条。句意：我妈妈早餐通常煮面条。 4. 【答案】sometimes 【解析】转折，有时候做面包。句意：但有时候她做面包。 5. 【答案】never 【解析】汉堡不健康，从来不吃。句意：我从不吃汉堡，因为对健康不好。 二、语法填空 根据上下文和首字母提示，在空白处填入一个适当的单词。 I'm a student at Sunshine Middle School. I enjoy my school life very much. Our school begins _______ 8 o’clock every morning. _______ Monday mornings, we do morning exercises first. Then our lessons start _______ autumn. I o_______ read books in the school library after class, but I s _______ go there on rainy days. I like Chinese best. I a _______ take notes carefully in Chinese classes. We have Biology classes _______ Tuesdays and Thursdays. _______ the afternoon, we take part in different afterschool activities. I am in the school volleyball team. We u _______ play volleyball on Friday afternoons, and we n _______ miss our team training. 【答案】 1. at 2. On 3. in 4. often 5. seldom 6. always 7. on 8. In 9. usually 10. never 【解析】 1. 【答案】at 【解析】具体时刻 8 o’clock 前用 at。句意：我们学校每天早上八点开始上课。 2. 【答案】On 【解析】Monday mornings 是具体某天早上，on 放句首大写。句意：周一早上我们先做早操。 3. 【答案】in 【解析】季节 autumn 前用 in。句意：然后秋天课程开始。 4. 【答案】often 【解析】首字母 o，频度副词 often 经常。句意：下课后我经常去学校图书馆看书。 5. 【答案】seldom 【解析】首字母 s，but 表转折，下雨天很少去图书馆。句意：但下雨天我很少去那里。 6. 【答案】always 【解析】首字母 a，语文课上我总是认真记笔记。句意：语文课上我总是认真记笔记。 7. 【答案】on 【解析】星期 Tuesdays and Thursdays 前用 on。句意：我们周二和周四有生物课。 8. 【答案】In 【解析】泛指下午 in the afternoon，句首大写。句意：下午我们参加不同的课外活动。 9. 【答案】usually 【解析】首字母 u，周五下午我们通常打排球。句意：周五下午我们通常打排球。 10. 【答案】never 【解析】首字母 n，从不错过球队训练。句意：我们从不错过球队训练。 1 / 12 学科网（北京）股份有限公司 $ Unit 4 School days核心语法精练·原卷版 （时间介词 & 频度副词） 目录 二、考点夯基 3 一、单项选择 3 二、用正确的时间介词或频度副词填空 4 三、句型转换 5 四、翻译句子 6 一、短文选词填空 6 二、语法填空 7 一、表示时间的介词on/in/at 介词 用法 示例 on 用在表示具体的日期、星期几、特定的节日(一天)、具体某一天的上午、下午或晚上前。 on October 1st on Friday on Children’s Day on Monday morning in 用于年、季节、月份前,也可以泛指在上午、下午或晚上。 in 2020 in winter in March in the afternoon at 用于表示具体时刻、年龄或noon、 night等前。 at 8:00 at six(years old)/at the age of six at noon 注意： (1)如果节日不止一天,而是持续一段时间,介词应用at。如at the Spring Festival "在春节(期间)"。 (2)时间状语前不用介词的两种情况： 1　 当时间状语中含有this、 that、 these、 those、 last、 next、 every、 each等修饰语时; 2　 当时间状语是today、 tonight(今晚)、 tomorrow morning/afternoon/evening等时。 例句： 1　 I go to school on foot every morning. 我每天早上步行去上学。 2　 I’m at home tonight. 我今晚在家。 二、频度副词 基本概念 常考的频度副词（频率由低到高） 表示动作发生的频率常用频度副词 1. 常考的频度副词 频度副词 用法 never 意为"从不",表示否定意义。 seldom 意为"很少,不常",表示否定意义。 sometimes 意为"有时",表示动作时有发生,间隔较长。 often 意为"经常,时常",表示动作或状态的反复,中间有间断。 usually 意为"通常",表示习惯性动作或状态,很少有例外。 always 意为"总是,一直",表示的频率是最高的,表示动作反复发生。 2. 频度副词在句中的位置 位置 例句 频度副词+行为动词 We often play basketball after school. 放学后我们经常打篮球。 be动词、助动词、情态动词+频度副词 He is never late for school. 他上学从不迟到。 She can sometimes win a match. 她有时能赢得比赛。 We do not usually go swimming. 我们不经常去游泳。 注意： 1　 有时为了表示强调,会把sometimes、 usually、 always、 often等频度副词放在句首; 2　 还会把often放在句末,这时可用very或quite来修饰often。 例句： 1　 Sometimes my mum goes to work on foot. 有时我妈妈步行去上班。 2　 I like playing computer games, but my dad doesn’t let me play them very often. 我喜欢玩电脑游戏,但是我爸爸不让我经常玩。 3. 对频度副词进行提问 提问词 例句 how often He seldom does morning exercises. 他很少做早操。（对划线部分进行提问） → How often does he do morning exercises? 他多久做一次早操? 一、单项选择。 1. I go to school ______ 7:00 every morning. A. in B. on C. at D. for 2. We have PE lessons ______ Monday afternoon. A. in B. on C. at D. of 3. He ______ late for school. A. is never B. never is C. never does D. does never 4. ______ do you play football? —Sometimes. A. How long B. How often C. How far D. How many 5. They go to the park ______ weekends. A. in B. on C. at D. of 6. She ______ watches TV in the evening. A. often is B. is often C. often does D. often 7. We have no classes ______ last Friday. A. in B. on C. at D. / 8. He ______ plays computer games, so he is good at study. A. always B. usually C. seldom D. often 9. Children like playing ______ summer. A. in B. on C. at D. for 10. I ______ walk to school, but sometimes I ride a bike. A. never B. usually C. seldom D. ever 11. The meeting is ______ the morning of September 10th. A. in B. on C. at D. for 12. They ______ late. They are hard-working. A. are never B. never are C. always are D. are always 13. ______ I get up late on Sundays. A. Seldom B. Sometimes C. Always D. Usually 14. He doesn’t ______ eat snacks between meals. A. never B. seldom C. often D. always not 15. We have lunch ______ noon at school. A. in B. on C. at D. for 16. She ______ her homework after school every day. A. always do B. always does C. does always D. do always 17. I go swimming ______ every summer. A. in B. on C. at D. / 18. He ______ tells lies, so we all trust him. A. always B. usually C. seldom D. never 19. How often ______ you ______ basketball? A. do; play B. does; play C. do; plays D. does; plays 20. They ______ busy on weekdays. A. often are B. are often C. often do D. do often 二、用正确的时间介词或频度副词填空 1. We have lessons ______ the morning. 2. Our lessons begin ______ 8:15 a.m. 3. I go to school ______ Monday. 4. He plays football ______ Saturday afternoon. 5. They go out ______ weekends. 6. I get up early ______ every morning. 7. She is busy ______ winter. 8. We have no classes ______ Sunday. 9. He is______ (从不) late for school. 10. I ______ (通常) walk to school. 11. They ______ (经常) do their homework after school. 12. She ______ (很少) watches TV at night. 13. ______ (有时) I play basketball with my friends. 14. My mother ______ (总是) cooks dinner for me. 15. We have a party ______ the afternoon of October 1st. 16. He meets his friends ______ lunchtime. 17. I go to the park ______ last Sunday.（不填/填介词） 18. They will have a trip ______ next week.（不填/填介词） 19. Cats sleep ______ the day and hunt ______ night. 20. I ______ am late for class. (never) 三、句型转换 1. He is always busy on weekdays.（改为否定句） He ______ ______ busy on weekdays. 2. I usually go to school on foot.（对划线部分提问） ______ ______ ______ ______ ______to school on foot? 3. They often play football after school.（改为一般疑问句） ______ they ______ ______ football after school? 4. She seldom watches TV at night.（改为同义句） She ______ ______ watch TV at night. 5. We have lessons in the morning.（改否定句） We ______ ______ lessons in the morning. 6. Sometimes I walk home.（改为同义句） I ______ walk home. 7. She is often late for school.（改否定句） She ______ ______ late for school. 8. He always does his homework carefully.（改否定句） He ______ ______ his homework carefully. 9. They sometimes go shopping on Sunday.（对划线提问） ______ ______ ______ go shopping on Sunday? 10. Millie often reads books in the library.（用never改写句子） Millie ______ ______ books in the library. 四、翻译句子 1. 我通常晚上九点上床睡觉。 ____________________________________________________ 2. 她工作日很少去电影院。 ____________________________________________________ 3. 他上学从不迟到。 ____________________________________________________ 4. 我们有时候下课后打排球。 ____________________________________________________ 5. 我的妈妈几乎不在空闲时间看卡通片。 ____________________________________________________ 一、短文选词填空 always, usually, sometimes, seldom, never My name is Kitty, a Grade 7 student. I ____1____ get up at 6:40 a.m. on school days. I ____2____ miss morning reading. My mum ____3____ cooks noodles for breakfast, but ____4____ she makes bread. I ____5____ eat hamburgers because they are bad for my health. 二、语法填空 根据上下文和首字母提示，在空白处填入一个适当的单词。 I'm a student at Sunshine Middle School. I enjoy my school life very much. Our school begins _______ 8 o’clock every morning. _______ Monday mornings, we do morning exercises first. Then our lessons start _______ autumn. I o_______ read books in the school library after class, but I s _______ go there on rainy days. I like Chinese best. I a _______ take notes carefully in Chinese classes. We have Biology classes _______ Tuesdays and Thursdays. _______ the afternoon, we take part in different afterschool activities. I am in the school volleyball team. We u _______ play volleyball on Friday afternoons, and we n _______ miss our team training. 1 / 12 学科网（北京）股份有限公司 $