动词不定式讲解

非谓语动词一、英语句子需要遵循一个总原则：一个句子只能有一个动词。当一个句子必须要出现两个或两个以上的动词才能完整表达一个意思时，为了不违法总原则，英语有四种处理方式： 1. 切分成两个或者多个句子 She is a girl. She likes English 2. 将一个谓语动词做主句，其余动词改成从句 She is the girl who likes singing. 3. 添加and, but, or, when, because, not only.but also, either.or 等连词变成并列结构 She got off the bus, but left her handbag on her seat. 4. 将其中一个动词变成非谓语动词形式 She got off the bus, leaving her handbag on her seat.二、 非谓语动词使用条件：一个句子当中，已经存在一个主句（谓语动词），又没有连词(and,but,or等)的情况下，还有别的动词出现时，这时就要用非谓语动词三、非谓语除了不能做谓语外，其他成分都可以做 不定式（to do）四、 非谓语动词三种形式 分词 现在分词（doing） 过去分词 ( done ) 动名词 (doing)五、非谓语动词解题技巧：1. 判断是不是用非谓语动词 （1.看有没有逗号2.看有没有谓语3.看有没有连词。要牢记英语中逗号不能连接两个句子，一个句子如果没有连词只能有一个谓语）2. 判断是主语和动词是主动还是被动关系 3. 判断时间, 确定非谓语动词和主句动词谁先发生，谁后发生不定式的用法不定式构成一般式完成式进行式主动关系to doto have doneto be doing被动关系to be doneto have been done不定式动词和谓语动词发生的时间关系不定式的动作和谓语动作同时发生，或发生谓语动作之后he seems to know a lot不定式的动作发生在谓语动作之前I regretted to have told you a lie.不定式的动作和谓语动作同时发生Im glad to be talking with you不定式否定形式在to前加not. 即not to.不定式充当的成分主语，宾语，表语，定语，状语，宾补【不定式做主语】1. 不定式作主语时，谓语用单数。To succed calls for hard work.(= It calls for hard work to succeed.)2. 用it 作形式主语，把不定式放在谓语后面，避免头重脚轻。常用的结构：句型一：It takes/took sb+时间 to do ：it takes me ten minitues to walk there句型二：It is +形容词+ of sb to do sth 这个句型的形容词一般是表示性格、品德、心智能力，表示主观感情或态度的形容词，如careless, clever, considerate, foolish, good, impolite, kind,naughty, nice,silly, stupidIts very nice of you to help me.句型三：It is +形容词+ for sb to do sth 这个句型的形容词一般是表示事物的特征，特点，表示客观形式的形容词，如easy, hard, difficult,interesting, impossible.It is very hard for him to study two languages.形式主语 不定式是真正的主语用for还是of的辨别方法：用for或of 后面的逻辑主语做句子的主语，用介词前面的形容词做表语造个句子，意思通顺的用of, 不通顺用forYou are nice (通顺，用of) he is hard (不是要表达的意思，不通顺，用for)【不定式做宾语】1. 只能接to do 做宾语的：决定想做需要计划，同意能做被用来做的事Decide to do sth 决定做某事 agree to do sth同意做某事Want/would like to do sth 想要做某事 afford to do sth能做某事Need to do sth 需要做某事 be used to do sth被用来做某事迫不及待下决心，能过去常常未能走的事cant wait to do sth迫不及待地想要做某事 sed to do sth过去常常做某事decide/determie to do sth下决心做某事 fail to do sth未能做某事care to do sth想要做某事 hesitate to do sth 犹豫做某事offer to do sth 主动提出做某事 choose to do sth 选择做某事 plan to do sth 计划做某事 learn to do sth 学会做某事Arrange to do sth 安排做某事 demand to do sth 要求做某事Manage to do sth 设法做某事 pretend to do sth 假装做某事 Prepare to do sth 准备做某事 hope to do sth 希望做某事I decide to study hard.2. 特殊疑问句+不定式 , 作宾语I dont know what to do next/ how to do it next. 3. 用it 作形式宾语: 不定式作宾语时，如果还带有宾语补足语，往往把不定式放在宾语补足语之后，用it 作形式宾语I find to learn a foreign language necessary= I find it necessary to learn a foreign language. （it 作形式宾语）常用it做形式宾语的动词：find, think, consider, feel, make + it (形式宾语)+形容词+ to do【不定式做宾补】1. 用不定式做宾补的动词有：请求与命令 答应警告允许提醒和帮助Ask sb to do sth 请求某人做某事 promise sb to do sth答应某人做某事Order sb to do sth命令某人做某事 warn sb to do sth警告某人做某事allow sb to do sth允许某人做某事想要期待邀请，建议鼓励 remind sb to do sth提醒某人做某事Want sb to do sth想要某人做某事 help sb (to) do sth帮助某人做某事Expect/wish/hope sb to do sth期待某人做某事 Teach sb to do sth 教某人做某事Invite sb to do sth邀请某人做某事 Force sb to do sth 强迫某人做某事Advise sb to do sth 建议某人做某事 persuade sb to do sth 劝服某人做某事Encourage sb to do sth鼓励某人做某事I want you to speak to Tom. 宾语 宾补2.省略to的不定式做宾补（即结构为：let sb do sth），这些词有：（一感）feel（二听）hear, listen to，（三让）have, let, make，（五看）notice, see, watch, observe, look at 注意：这些动词变为被动语态后，必须带to。They saw the boy fall off the tree. The boy was seen to fall off the tree.cannot but do sth 不得不做某事 I cannot but admire her courage.Would rather do sth 宁愿做某事Why not do sth 为什么不做某事 Why not join us in the game?Ought to do sth 应该做某事Had better do sth 最好做某事 You had better answer his letter right now.prefer+不定式+rather than+动词原形 宁愿做某事.而不愿做另一事”。I prefer to walk there rather than go by bus. 我宁愿走着去，而不愿坐公共汽车去。He prefers to read rather than watch television.他喜欢 读书而不喜欢看电视。3. help后面作宾语补足语的不定式可以带to,也可以不带to. 即“help sb (to) do sth” I often help him（to）clean the room. I helped him (to) find his things. 宾语 宾补 4. 介词except, but，besids前出现了do的各种形式，后面不定式不带to, 如果没有do, 就带to I can do everything except cook. I have no choice but to go What do you like to do besides sleep?5. 两个并列的动词不定式，第二个to可以省略。Id like to lie down and (to) go to sleep.6. 不定式to不能省略1) 当一个不定式与另一个不定式对比时: To try and fail is better than not to try at all.2) 当省略前面出现过的动词时，动词可省，但to必须保留The boy wanted to ride his bicycle in the street, but his mother told him not to.-Ill be away on a business trip. Would you mind looking after my cat?-Not at all. Id be happy to.3) 当句中有并列不定式时They have come to talk, to sing, to get drunk. 【不定式做表语】不定式可放在be动词后面，构成表语。My question is when to leave.His dream is to be a doctor.【不定式做状语】1. 做目的状语，常以下面形式出现: 1) to do为了. I got up early to catch the early bus. 他起的很早为了赶上早班车2) in order to 为了.（用在句首和句中）I got up early in order to catch the early bus.3) so as to 为了. （只能用在句中，不能放在句首）I got up early so as to catch the early bus.4) Only to “仅仅为了”I come here only to say good-bye to you 我来这就是为了跟你道别 2. 作结果状语，表事先没有预料到的结果，常和too.to, enough.to, so.as to , such.as to. , only to连用1) too.+形容词/副词.to do sth: 太.以至于不能.He is too young to go to school 他太小了以至于不能上学2) 形容词/副词 + enough to do sth: 足够.而能做某事He is old enough to go to schoool 他足够大了能上学了3) So + 形容词/副词.as to（那么地以至）She was so angry as to be unable to speak.她气的连话都说不出来了4）such + (a,an) + 名词as to. She is such a good student as to be repected by all the students.5）only to 是“不料却., 结果却.”, 表示没有预料到的或事与愿违的结果He hurried to the post office only to find it was closed.3. 做原因状语：We were very excited to hear the news. Im glad to see you4. 做条件状语：To turn to the left , you could find a post office.【不定式做定语】不定式做定语，应放在被修饰词的后面,不定式与所修饰的词有三种关系动宾关系：I have a lot of work to do. （如果不定式的动词是不及物动词，不定式中要有介词） He is looking for a room to live in ( live in a room ) There is nothing to worry about (worry about nothing)主谓关系：He is the first person to think of the idea. 同位关系：He has got a chance to go abroad.【什么情况下用不定式主动形式表示被动关系】1. 动词不定式在名词后面作定语，不定式和名词之间有动宾关系时，又和句中另一名词或代词构成主谓关系, 不定式的主动形式