Unit 2 Communication 宾语从句引导词 if whether-2025-2026学年八年级英语下册语法知识点全解（北师大版）

初二下册北师大版 Unit2 Communication语法专项突破 语法专版 宾语从句引导词if/whether 8年级下册Unit2 考频分析 8下北师大版中，宾语从句引导词f/whether是核心语法点，考频占从句类语法的15%左右，主要 分布在试卷关键题型：单项选择(1-2题)、完形填空(1-2题)、阅读理解（间接考察句意理解）、 书面表达（影响句子逻辑连贯性）。在语境应用类题目中，if/whether的选择及与其他引导词的辨析 常是解题难点。 考查内容 。基本功能辨析：f与whether在引导宾语从句时表示“是否”的共性用法，及在介词后、与or not连 用时只能用whether的特殊规则 ·句式转换应用：直接引语中一般疑问句转换为间接引语时，引导词if/whether的选用及语序调整（陈 述句语序) 。语境语义匹配：在表达“是否”含义的宾语从句中，结合上下文语境选择合适的引导词，区分f表 “如果”时的条件状语从句用法 知识点一：宾语从句引导词if/whether的用法 1.基本功能（连接宾语从句，表“是否”） ·用于及物动词、介词或形容词后引导宾语从句，表达不确定的疑问概念。 。例句：(1)I don't know if/whether he will come tomorrow.(及物动词know后，表“是否会来”)(2) They are talking about if/whether the movie is interesting.(介词about后，表“电影是否有趣”) 2.与that的区别（表“是否”vs表陈述） 。if/whether引导有疑问意义的宾语从句，不可省略；hat引导陈述意义的宾语从句，可省略。 。例句：(I)She asked if/whether I had seen the film.(有疑问：是否看过)(2)She said(仙hat)she had seen he film.(陈述事实：看过电影) 初二下册北师大版 Unit2 Communication语法专项突破 3.特殊用法（只能用whether的情况) 。与or not直接连用时：I wonder whether or not we should go.(不能用if or not) ·作介词宾语时：It depends on whether it rains tomorrow.(介词on后不能用if) 。位于句首引导主语从句时：Whether he will help us is still unknown.(句首主语从句不能用if) 4.时态呼应（主现从任意，主过从过) 。主句为现在时/将来时，从句可根据实际情况用任意时态：主句为过去时，从句用过去相关时态。 ·例句：(1)He asks if she lives here.(主现从现)(2)He asked if she lived here.(主过从过)(3)He will ask if she has finished the work.(主将从现完) 知识点二：if/whether引导宾语从句的用法 1.基本含义（表“是否”） 。用于动词后，引导宾语从句，意为“是否”，表示对某件事的不确定性或询问可能性。 。可互换使用，常置于及物动词（如know,ask,wonder,.decide等）或形容词（如sure,uncertain等）之 后。 ·例句：(I)Idon't know if/whether he will come tomorrow.(我不知道他明天是否会来。)(2)She asked if/whether the answer was correct..(她问答案是否正确。) 2.语序规则（陈述语序） ·宾语从句必须用陈述语序，即“连接词+主语+谓语+其他”，不可用疑问语序。 。错误：He asked if/whether was she at home. 。正确：He asked if/whether she was at home.(他问她是否在家。) ·无论主句是陈述句还是疑问句，从句始终保持陈述语序。 ·例句：Do you know if/whether they have finished the work?(你知道他们是否完成了工作吗？) 3.时态呼应（主从时态一致) ·主句为一般现在时/一般将来时，从句根据实际情况用任意时态。 ·例句：(I)I wonder if/whether he is listening to music now.(现在进行时)(2)She will ask if/whether they went to the park yesterday.(一般过去时) ·主句为一般过去时，从句用相应的过去时态（一般过去时、过去进行时、过去将来时、过去完成时）。 。例句：(I)He asked if/whether she lived here.（一般过去时)(2)They wanted to know if/whether we were watching TV at8p.m.last night.(过去进行时) 初二下册北师大版 Unit2 Communication语法专项突破 。从句表客观真理时，用一般现在时，不受主句时态影响。 。例句：The teacher told us if/whether the earth goes around the sun.(地球绕太阳转是客观真理，用一般 现在时goes) 4.与or not的搭配 ·whether可直接与or not连用，if一般不直接连用（需分开：if.or not)。 。例句：(I)I'm not sure whether or not he will agree.(正确)(2)I'm not sure if he will agree or not.(正 确) 。错误：I'm not sure if or not he will agree. 5.特殊句式中的应用 。作介词宾语时，只能用whether,不用if。 ·例句：We are talking about whether we should help them.(about是介词，后接whether引导的宾语从 句) ·位于句首引导主语从句或表语从句时，只能用whether。 ·例句：Whether he can come depends on the weather.(主语从句，位于句首用whether) ·后接动词不定式时，只能用whether(whether to do sth.)。 ·例句：She hasn't decided whether to go there by bus or by bike.(whether+不定式结构) 知识点三：宾语从句引导词if/whether 1.基本用法（中考核心) ·if表示“是否”，引导一般疑问句转化的宾语从句，句末用陈述句语序→例句：Idon't know if he will come tomorrow. ·whether表示“是否”，引导一般疑问句转化的宾语从句，可与or not连用→例句：She asks me whether I like English or not 。两者通用场景：主句谓语动词为know,ask,wonder等时→例句：He asks if/whether the train will arrive on time. 2.特殊用法（中考易错) 。与or not连用时只能用whether-→例句：I'm not sure whether he will agree or not. 。位于句首引导宾语从句时只能用whether-→例句：Whether it will rain tomorrow is still unknown. 。跟在介词后作宾语时只能用whether-→例句：We are talking about whether to go to the park. 3 初二下册北师大版 Unit2 Communicatio1语法专项突破 3.与hat的区别（中考常考） 。if/whether引导有疑问意义的宾语从句（是否）→例句：She wonders if she can pass the exam. 。that引导陈述句转化的宾语从句（无意义，可省略）→例句：I know(hat)he is a good student. 。否定转移提示：主句谓语为think,believe等时，否定词前移→例句：Idon't think if/whether he is ight.（正确：I don't think he is right.)→注：此时从句不用if/whether,直接用that(可省略) 考法精析 考法一：if/whether用法辨析 核心：根据语境判断宾语从句中引导词if/whether的正确使用，尤其是只能用whether的特殊情况 真题1（单项选择)： I wonder_we should go to the party or not. A.if B.whether C.that D.what 答案：B 解析：与or not直接连用时，宾语从句引导词只能用whether,不能用if。 真题2（语法填空）： It depends on(if/whether)the weather is fine tomorrow. 答案：whether 解析：作介词on的宾语时，宾语从句引导词只能用whether,不能用if。 考法二：直接引语转间接引语中的宾语从句引导词与语序综合辨析 核心：根据直接引语的句式类型（陈述句/一般疑问句/特殊疑问句），正确选择宾语从句引导词，并 将从句调整为陈述语序，同时关注人称、时态等变化 真题1（句型转换)： She asked,"Will you go to the park with me tomorrow?She asked. -go to the park with_ 答案：if/whether I would her the next day 解析：直接引语为一般疑问句，用if/whether引导宾语从句；从句用陈述语序，you随主句宾语her 变化为I:主句为过去时，will变为would:时间状语tomorrow变为the next day。 真题2（单项选择）： He said to me,"Where did you buy this book?"He asked me_. A.where did I buy this book B.where I bought that book C.where I buy this book D.where do I buy that book 答案：B 解析：直接引语为特殊疑问句，用原疑问词whre引导：从句需用陈述语序（主语I在前，谓语 4 初二下册北师大版 Unit2 Communicatio1语法专项突破 bought在后)，排除A、D:主句为过去时，从句用过去相关时态，buy变为bought:指示代词this 变为that,故选B。 考法三：直接引语变间接引语中的if/whether用法及时态呼应 核心：掌握一般疑问句转为间接引语时用if/whether引导，需调整为陈述语序并遵循”主过从过”的 时态呼应规则 真题1（单项选择）： He asked,"Does Mary go to school by bike?"He asked if to school by bike. A.Mary goes B.Mary went C.does Mary go D.did Mary go 答案：B 解析：直接引语为一般疑问句，转为间接引语用f引导，需用陈述语序（排除C、D):主句谓语 asked为过去时，从句时态需呼应为过去时，go的过去式为went。 真题2（语法填空)： The teacher said to us,"Will you finish the project tomorrow?The teacher asked us whether we_ (finish)the project the next day. 答案：would finish 解析：直接引语为一般疑问句，转为间接引语用whether引导：主句said为过去时，从句需用过去 将来时(will→vould),故填would finish。 解题小妙招 if whether用法妙招 if whether虽同义，特殊情况要牢记： 与or not紧相连，介词之后用whether: 直引疑问变间接，二者均可引从句。 间接引语转换妙招 直引变间接，引导词先确定： 陈述用that可省略，一般疑问if/whether: 特殊疑问用原词，从句语序要陈述： 人称随主句调整，时态前后要呼应： 时间状语需转换，tomorrow改next day,now变then记心间。 真题演练 演练一：单项选择试题 1.I can't decide to take the bus or ride a bike to school. 初二下册北师大版 Unit2 Communication语法专项突破 A.if B.whether C.that D.when 2.Could you tell me_the nearest post office is? A.what B.how C.where D.who 3.He asked me _I had finished my homework. A.if B.that C.what D.which 4.She doesn't know _her father will come back tomorrow. A.weather B.if C.that D.what 5.The teacher told us_the earth goes around the sun. A.if B.whether C.that D.what 6.I wonder-they will arrive here on time. A.that B.if C.what D.who 7.He asked meI was doing at that time. A.what B.that C.if D.who 8.Could you please tell methe library closes today? A.what B.when C.that D.who 6 初二下册北师大版 Unit2 Communication语法专项突破 9.She said she would go to the park with her friends. A.if B.whether C.that D.what 10.I don't knowhe will come or not. A.if B.whether C.that D.what 演练二：填空试题 1.I don't know(if/whether)he will come to the party. 2.She asked me_I had seen her keys 3.Could you tell me-the nearest hospital is? 4.He wondered his parents would be angry with him. 5.I want to know-you are interested in playing basketball. 6.The teacher asked we had finished our homework 7.She asked me_I was from. 8.I don't knowhe will arrive here. 9.He askedI could help him with his English 10.Could you tell methe train leaves? 演练三：语法填空试题 Tom is a student.One day,his friend Lily askedhim 1.-he would go to the cinema with her this weekend. Tom said he didn't know 2.his parents would allow him to go.He told Lily that he would ask his parents and let her know 3.-he could go or not.Lily said she would wait for his reply.Later,Tom asked his mother 4.-they had any plans for the weekend.His mother said they might go to visit his grandparents. Tom wondered 5.-they would come back on Sunday.His mother told him 6.-they would come back in the afternoon.Tom then called Lily and told her 7.-he couldn't go to the cinema with her because he had to visit his grandparents.Lily asked 8.-they could go to the cinema next weekend.Tom said he was not sure 9.-he would be free next weekend,but he would let her know as soon as possible.Lily said she understood and hoped 10.-they could go together next time. 7 初二下册北师大版 Unit2 Communication语法专项突破 答案区 演练-：1B2.C3.A4.B5.C6B7.A8B9.C10B ì练二：1.if/whether2.if/whether3.where4.if/whether5.if/whether6.if/whether7.where8.when 9.if/whether 10.when 1.if/whether 2.if/whether 3.whether 4.if/whether 5.when 6.that 7.that 8.if/whether 9.if/whether 10.that 8