固定结构be going to, used to, have to, had better 变为被动态时,只需将其后的动词变为被动 态。如: Trees should not be pla nted in summer. / The boy was made fun of by his classmates. Newspapers used to be sent here by the little girl. 汉语有一类句子不出现主语,在英语中一般可用被动结构表示。如: It is believed that… It is genera lly considered that… It is said that… It is well known that… It must be pointed out that… It is supposed that… It is reported that… It must be admitted that… It is hoped that… 下面主动形式常表示被动意义:如: The window wants/needs/requires repairing. The book is worth reading twice. The door wont shut. / The pla y won’t act. The clothes washes well. / The book sells well. The dish tastes delicious. / Water feels very cold. 下面词或短语没有被动态: lea ve, enter, reach, become, benefit, cost, equal, contain, last, lack, fit, fail, have, appe ar, happen, occur, belong to, take place, break out, come about, agree with, keep up w ith, consist of, have on, lose heart 等等 七.情态动词 I. 情态动词基本用法: 情态动词用法否定式疑问式与简答 can 能力(体力,智力,技能) 允许或许可(口语中常用) 可能性(表猜测,用于否定句或疑问句中) can not / cannot /cant do Can?do?? Yes,…can. No,…can’t. could could n’t do ma y 可以(问句中表示请求) 可能,或许(表推测) 祝愿(用于倒装句中) ma y not do May?do?? Yes,?ma y. No,…mustnt/can’t. might might not do Might…do…? Yes,…might No,…might not. must 必须,应该(表主观要求) 肯定,想必(肯定句中表推测) must not/mustnt do Must?do?? Yes,?must. No,…needn’t/don’t have to. have to 只好,不得不(客观的必须,有时态人称变化) dont have to do Do?ha ve to do…? Yes,…do. No,…don’t. ought to 应当(表示义务责任,口语中多用should ought not to/oughtnt to do Oug ht…to do…? Yes,…ought. No,…oughtn’t. shall 将要,会 用于一三人称征求对方意见 用于二三人称表示许诺、命令、警告、威胁等shall not/sha nt do Shall?do?? Yes,…shall. No,…shan’t. should 应当,应该(表义务责任) 本该(含有责备意味) should not/should nt do Should?do?? will 意愿,决心 请求,建议,用在问句中would 比较委婉will not/wont do Will ?do?? Yes,…will. No,…won’t. would would not/would n’t do dare 敢(常用于否定句和疑问句中) dare not/daren t do Dare?do?? Yes,…dare. No,…daren’t. need 需要 必须(常用于否定句和疑问句中) need not/neednt do Need?do?? Yes,…must. No,…needn’t. used to 过去常常(现在已不再) used not/usednt/usen’t to do didn’t use to do Used…to do…? Yes,…used. No,…use(d)n’t. Did …use to do…? Yes,…did. No,…didn’t. II. 情态动词must, ma y, might, could, can 表示推测: 以must 为例。must + do(be)是推测现在存在的一般状态进行;must + be doing 推 测可能正在进行的事情;must +have done 是推测可能已经发生过的事情。 1. must“肯定,一定”语气强,只用于肯定句中。 He must be a ma n from America. / He must be talking with his friend. / He must have already arrived there. 2. ma y 和might“也许”,后者语气弱,更没有把握。可用于肯定句和否定句。 He ma y not be at home. / They might have finished their task. 3. can 和could “可能”,could 表示可疑的可能性,不及cant 语气强,用于肯定、 否定、疑问句中。 The weather in that city could be cold now. We could have walked there; it was so near.(推测某事本来可能发生,但实际上没 有发生) Can he be in the office now? No, he cant be there, for I saw him in the library just no w.(语气很强,常用于疑问句和否定句中) III. 情态动词注意点: 1. can 和be able to: 都可以表示能力。但be able to 可以表达“某事终于成功”,而can 无法表达此意。Be able to 有更多的时态。另外,两者不能重叠使用。 2. used to 和would: used to 表示过去常常做现在已经不再有的习惯,而would 只 表示过去的习惯或喜好,不涉及现在。 3. need 和dare 作情态动词和实义动词的区别: 两者作情态动词时常用于否定句和疑问句。其形式为:neednt/daren ’t do;Need/ dare…do…? 做实义动词时可用于肯定句,否定句和疑问句。其形式为:need(needs/needed)/d are(dares/da red) to do, dont(doesn’t/didn’t) need/dare to do 八.非谓语动词 I. 非谓语动词的分类、意义及构成: 非谓语形式构成特征和作用 时态和语态否定式复合结构 不定式to do to be doing to have done to be done to have been done 在非谓语前加not for sb. to do sth. 具有名词,副词和形容词的 作用 在句中做主、宾、定、表和状语 分词现在分词doing having done being done having been done 具有副词和形容词的作用 在句中做定、表、宾补和状语 过去分词done 动名词doing having done being done having been done sbs doing 具有名词的作用 在句中做主、宾、定和表语 II. 做宾语的非谓语动词比较: 情况常用动词 只接不定式做宾语的动词