原因状语从句because since as-2025-2026学年八年级英语下册语法易错点精讲（教科版五四制）

初中外研版 【寒假专版】 8年级下册语法精讲 寒假专版 原因状语从句专项训练 寒假语法易错点精讲 学段：初中教材：教科外研版（五四制） 年级：8年级下册 语法认知 原因状语从句(because,since,,as)=用于说明主句动作或情况发生原因的从句，由because,since,. as引导，在句中作状语。 易错点讲解 易错点一：because,.since,as的语气强弱与用法混淆 讲解： because语气最强，强调直接原因，可回答why提问；since/as语气较弱，侧重已知或显而易见的 原因，通常位于句首，since稍正式，as更口语化。 例句：He stayed at home because he was ill..(直接原因)Since it's late,I should go now.(已知原因)As you are busy,I'll leave you alone.(显而易见的原因) 真题再现： l.(2024山东济南期中，外研版)-Why didn't you go to the party yesterday?一_I had to look after my sick mother A Because B Since C As D For 答案：A解析：回答why提问需用because,强调直接原因。 2.(2024北京朝阳区月考，外研版)一everyone is here,let's start the meeting A Because B Since C As D For 答案：B解析：句首表“既然所有人都到了”这一已知原因，since符合语境，比s更正式。 易错点二：because与so的连用错误 初中外研版 【寒假专版】 8年级下册语法精讲 讲解： 英语中because和so不可同时使用，二者只能选其一连接句子。 例句：Because he was tired,he went to bed early.→He was tired,.so he went to bed early.(不可说 Because he was tired,so he went to bed early.) 真题再现： 1.(2023天津和平区期末，外研版)_it rained heavily,_we stayed at home. A Because;so B Because;/C So;because D/;because 答案：B解析：because和so不可连用，此处表原因用because引导从句。 2.(2023河北石家庄期中，外研版)He did't buy the book一he had no money. A so B because C and D but 答案：B解析：表原因用because,句中已有结果，无需再用so。 易错点三：since/as引导从句时的位置错误 讲解： since/as引导原因状语从句时，通常位于句首；若置于句中，需用逗号与主句隔开。 例句：Since you don't like it,,I'll take it back.→I'll take it back,since you don't like it. 真题再现： 1.(2024辽宁沈阳月考，外研版)We decided to walk there一the bus was late A because B since C as D for 答案：B解析：从句位于主句后，表已知原因用sice,需用逗号隔开（此处选项中符合语法且 位置合理的为since)。 2.(2023山西太原期末，外研版)_you are free today,.why not go shopping with me? A As B Because C So D For 答案：A解析：句首表“既然你今天有空”这一显而易见的原因，s符合口语化语境。 易错点四：because与because of的混用 讲解： because是连词，后接从句；because of是介词短语，后接名词、代词或动名词。 例句：He failed because he was careless.→He failed because of his carelessness. 2 初中外研版 【寒假专版】 8年级下册语法精讲 真题再现： 1.(2024山东青岛期中，外研版)He couldn't come to the party一his illness. A because B because of C so D since 答案：B解析：空后“his illness”是名词短语，用because of。 2.(2023江苏南京月考，外研版)We had to stay at home_it was raining hard. A because of B because C as D since 答案：B解析：空后是完整从句“it was raining hard”,用because引导。 易错点综合演练 综合演练 I.单项选择（直击易错点） 1.-Why were you late for class this morning? A Because B Since C As D For 2.it's getting dark,we should return home now. A Because B Since C As D For 3.He didn't attend the meeting_he was on business. A so B because C and D but 4.They had to cancel the tripthe bad weather. A because B because of C since D as Ⅱ.用所给词的适当形式填空（强化易错点区分） l.because)he was ill,,he didn't go to school yesterday.(提示：注意与so的连用) 2.He failed the exam _(because)his laziness. 3.一(since)you have finished your homework,you can watch TV for a while.(提示：注意从句位 置) 4.We didn't go out-(as)it was raining heavily.(提示：注意从句位置) Ⅱ.短文填空（综合运用四大易错点） 用because,since,.as,because of填空，使短文完整通顺。 Hello,everyone!I'm Li Ming.I didn't go to the park with my friends yesterday 1.-I had to help my mom do housework.2.-my mom was busy with her work,she asked me to clean the rooms.3.-I 3 初中外研版 【寒假专版】 8年级下册语法精讲 was cleaning,I found my old toys.I was very happy 4.-seeing them.5.it was getting late,I stopped cleaning and put the toys away. V连词成句（聚焦易错句式） 1.because,he,was,tired,he,went,to,bed,early,( 2.it,rained,heavily,so,we,stayed,at,home,(. 3.since,everyone,is,here,let's,begin,the,lesson,(. 4.because of,the,traffic,jam,he,was,late,for,school,(. 参考答案 I单项选择 1.A2.B3.B4B Ⅱ.用所给词的适当形式填空 1.Because 2.because of 3.Since 4.as I.短文填空 1.because 2.Since 3.As 4.because of 5.Since V.连词成句 1.He went to bed early because he was tired. 2.It rained heavily,so we stayed at home. 3.Since everyone is here,let's begin the lesson. 4.He was late for school because of the traffic jam.