Unit 3 Sound Body, Sound Mind-2026-2027学年八年级英语上册语法专项（仁爱科普版）

Unit 3 Sound Body,Sound Mind 语法专项 章 语法概览 ★否定前缀non-,dis-,um-,mis-,im- ☆need用法(need to do/don'tneed to do/needn'tdo) 语法精讲精练一 1.否定前缀的定义与作用 否定前缀加在形容词、动词或名词前，使词义变为“不、非、相反、错误”等否定含义。掌握 常见否定前缀是中考词汇变形题和完形填空的高频考点。 前缀 基本含义 常见搭配词性 中考示例 “不、非” happy-一→unhappy（不开心 un- 形容词、动词 的) tie→untie(解开) agree-→disagree(不同 意)honest-→dishonest dis- “不、相反、消失” 动词、形容词、名词 (不诚实的) appear-→disappear(消 失) stop→non-stop(不间断 non- “非、不” 名词、形容词 的) smoker→non smoker（非吸烟者) understand-misunderstan mis- “错误、坏” 动词 d(误解) take→nistake (弄错) possible-→impossible（不 可能的)polite-一→impolite 形容词（用于pb/m开头的 im- “不、非” (不礼貌的) 词前) balance→imbalance（不 平衡) 注意：im-是im-的变体，im-通常用于以1、r开头的词前（如legal-→illegal, regular--→irregular),但中考重点只考im-,因此本讲只要求掌握in-o 2.否定前缀的用法规律（四大核心考点） (1)un-是最常用的否定前缀，多数形容词可直接加um- 规律：m-+形容词原级→反义词 important→nimportant(不重要的) usual→usual（不寻常的) 常见中考词：unable,.unfair,unfo1 gettable,.unhealthy,unlucky,nnecessary (2)dis常加在动词前，表示“做相反动作” 规律：dis-+动词→否定意义的动词 like→dislike（不喜欢) cover→discover(发现，注意词义变化) appear→disappear(消失) 形容词：honest→dishonest;able→disable(使残疾，中考常考名词disabled) (3)non-表示“非…的”，多用于合成词 规律：non-+名词/形容词，常带连字符或不带 non-stop（直达的，不停的) non-smoking（禁止吸烟的) non-fiction（非小说类文学作品) (4)mis-表示“错误地做…” 规律：mis-+动词→错误动词 ude1 stand→misunderstand(误解) lead→mislead（误导) take→mistake(n.错误；V.弄错) 注意：mis-有时也加在名词前，如misfortune(不幸) (5)m-只在以p,b,m开头的形容词前使用 规律：im-+形容词(p/bm开头)→否定 possible→impossible(不可能的) polite→impolite（不礼貌的) patient→impatient(不耐烦的) balanced→imbalanced（不平衡的)→较少考，但需识记 中考易错点：im-不能用于所有形容词，比如important的反义词是unimportant,不是 *imimportanto 3.易混辨析（中考必考） 易混点 说明 例句 happy-unhappy (V) agree-→disagree un-vs.dis- 有些词的反义词只能用其一，不可混用 (v)unagree (x) polite-→impolite(W)）unpolite(x) un-vs.im- 同词根不同变体 personal-impersonal (v)unpersonal (x) 否定前缀不改 kind（形)→unkind（形) appear 加前缀后仍为原词性 变词性 (动)→disappear(动) 个别词加前缀 后意义需整体 discover并非“不覆盖”而是“发现” cover-→discover(发现) 记忆 二、专项训练（中考/名校月考难度，每大题8-10小题） (一)单项选择 1.Its to finish so much work in such a short time.We need more help. A.possible B.impossible C.possibly D.imposible 2.-Why did you with your parents? A.agreement B.disagree C.disagree D.unagree 3.This is an story.I don't want to read it again. A.interesting B.interested C.unimportant D.important 4.Be careful!Don't the sign on the wall.It says "No smoking". A.misunderstand B.misread C.mistake D.miss 5.My father is a smoker;he never smokes in public A.non-smoker B.nonsmoking C.non-smoking D.smoker 6.The little boy was very to the old lady.He said"Thank you'loudly. A.impolite B.polite C.impolitely D.politely 7.Ifyou the problem,you may make a wrong decision. A.understand B.misunderstanding C.misunderstand D.misunderstood 8.-Do you like the movie? A.dislike B.like C.unlike D.dislike 9.The old man lives alone,but he never feels A.unhappy B.unlucky C.lonely D.alone 10.It's to drive after drinking.You may cause an accident. A.safe B.unsafe C.safety D.save (二)语法填空 阅读下面短文，在空白处填入括号内所给单词的适当形式（有时需要加否定前缀）。 My best friend Tom is a 1. (usual)boy.He always wears strange clothes and has 2. (common)ideas.But I like him because he is 3. (honest)and never tells lies.Last week,he 又 (appear)for three days.Everyone was woried.Later we found he had a 5. (understand)with his parents.They 6.(agree)about his future plan.Tom wanted to be an artist, but his parents thought it was 7. (possible)to make a living.Finally,with the help of his teacher, they 8. (cover)a good solution.Tom decided to study art part-time and still keep good grades. Now Tom is much happier.He said,"It's 9. (fair)to force children to do what they don't like.I will prove that my dream is not 10. (practical)." (三)完成句子 1.我认为他不可能完成这个任务。I think it is for him to finish the task 2.他误解了我的意思，所以生气了。He my meaning,so he got angry. 3.这个非吸烟区不允许吸烟。Smoking is not allowed in this area 4.他不同意我的看法，坚持自己的意见。He with me and stuck to his own idea 5.不礼貌的行为会让人不舒服。 behavior makes people uncomfortable. 6.这条裙子很不寻常，我看过之后很难忘记。This dress is very I can't forget it after seeing it. 7.请小心，不要误解这个问题的意思。Please be careful and don't the meaning of this question 8.他是一个不诚实的人，我不喜欢他。e is a person.I him. 9.在考试中粗心是不明智的。Itis to be careless in the exam. l0.这本书是非小说类作品，但很有趣。This is a book,but it's very interesting 三、参考答案 （一)单项 1.B;2.B;3.C;4.B;5.C;6.B;7.C;8.A;9.C;10.B 选择 (二)语法 1.unusual 2.uncommon 3.honest 4.disappeared 5.misunderstanding 填空 6.disagreed;7.impossible 8.discovered ;9.unfair 10.impractical (三)完成 1.impossible 2.misunderstood 3.non-smoking 4.disagreed 5.Impolite; 句子 6.unusual 7.misunderstand ;8.dishonest;dislike 9.unwise 10.non-fiction 章 语法精讲精练二 1.need的两种词性 need既可作为实义动词，也可作为情态动词。中考重点考查二者的区分及否定/疑问结 构。 词性 用法特点 肯定句 否定句 疑问句 有动词变化（三 单needs,过去 实义动词 Do you need to I need to go. I don't need to go. needed);后接to go? do 无人称、时态变 化；后接动词原 较少用于肯定句 情态动词 (正式文体) You needn't go. Need Igo? 形：多用于否定 句、疑问句 2.核心用法对比 (1)needto do (实义动词表“需要做”) 主语是有生命的人/动物，表示“某人需要去做某事”。 例：I need to finish my homework.(我需要完成作业。) 主语是物时，常用need doing(主动表被动)或need to be done。 例：The car needs washing/needs to be washed.(这车需要洗了。)→初二暂不深入，作 为拓展了解。 (2)don't need to do(实义动词否定，意为“不必做”) 结构：主语+don't/doesn't/didn't+need to do 例：You don't need to bring your dictionary.( 你不必带词典。) (3)needn't do(情态动词否定，意为“不必做”) 结构：主语+needn't+动词原形 例：You needn't come early.（你不必早来。) 意思与don't need to do完全相同，但needn't do更口语化、更直接。 3.易混考点辨析 易混点 例句 分析 You needn't go now./You needn't是“不必”，mustn't是 needn'tdo与mustn'tdo区别 mustn't go now. “不准、禁止” The window needs cleaning. need to do与need doing区别 need doing =need to be done, The window needs to be (物作主语) 主动表被动 cleaned. need作为实义动词的疑问句 Does he need to leave now? 借助助动词do/does/did 直接提前，回答：Yes,he need作为情态动词的疑问句 Need he leave now? must./No,he needn't. 4.常见句型归纳 肯定句型：主语+ need to do sth. 否定句型：主语+don't/doesn't/didn't need to do sth. 或主语+needn't+do sth, 一般疑问： Do/Does/Did+主语+need to do?或Need+主语+do? 特殊疑问：疑问词+ do/does/did+主语+need to do？或疑问词+need+主 语+do? 二、专项训练 (一)单项选择（共8题） 从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。 1.You to bring your student card tomorrow.The teacher asked everyone. A.need B.needn't C.don't need D.needs 2.-Must I finish the report today? A.mustn't B.needn't C.don't need D.shouldn't 3.We worry about the test.We have prepared well. A.needn't B.don't need C.doesn't need D.need to 4.Lily to clean her room every weekend.It's her duty. A.needs B.need C.needing D.needn't 5.-Does your mother to go shopping? A.need B.needs C.needed D.needing 6.You water the flowers now.They are still wet. A.needn't B.don't need C.need D.mustn't 7.The floor is dirty.It cleaning A.need B.needs C.needing D.to need 6 I hand in this form now? A.Must B.Need C.Do D.Does (二)语法填空（共10空) 阅读下面短文，在空白处填入括号内所给单词的适当形式。 Tom is my best friend.He is a helpful boy.Last week,he 1. (need)to help his mother clean the house because his father was ill.He didn't complain.After that,he 2. (need)to do his homework.He worked hard Today,his mother tells him,"You 3. (not need)to do the cleaning today.I have already done it.”Tom smiles and says,“You4. (need)to take a rest,Mom.Let me help you." On weekends,Tom often asks me,"5. (Need)we go to the park together?"I always say,"Yes,we 6. (need)to enjoy ourselves.But sometimes,if it rains,we 7. (needn't)go. Tom is a good example.He knows what he 8. (need)to do and what he 9. (not need)to do.I think I 10. (need)to learn from him. (三)完成句子（共10题） 1.你需要每天练习英语。 You practice English every day 2.你们不必来这么早。 You come so early. You come so early 3.我需要给妈妈买一份生日礼物。 I buy a birthday gift for my mom. 4她不需要自己洗衣服，妈妈会帮她。 She wash clothes by herself. 5.我们不需要害怕犯错误。 We be afraid of making mistakes. We be afraid of making mistakes. 6.他需要按时完成作业吗？ he finish homework on time? 7.这棵树需要浇水了。 The tree (两种写法：need doing/need to be done) 8你不必告诉我答案，我自己能解决。 You tell me the answer;I can solve it myself. 9.你们需要带伞吗？可能下雨。 you bring umbrellas?It may rain. 10.我弟弟需要每天早上六点起床。 My brother get up at six every morning. 三、参考答案 (一)单项 1.A;2.B;3.A;4.A氵5.A;6.B;7.B;8.B 选择 (二)语法 1.needed 2.needed 3.don't need/needn't 4.need 5.Need 6.need 7.needn't 填空 8.needs 9.doesn't need 10.need 1.need to 2.don't need to /needn't 3.need to 4.doesn't need to 5.don't need to (三)完成 句子 /needn't 6.Does,need to 7.needs watering/needs to be watered 8.needn't/ don't need to 9.Do,need to 10.needs to