• 2.跟在作表语的形容词或过去分词的后面 例如:I„m sorry to hear that.听到这事我感到 很难过 3.用在too... to...结构中。例如: He is too young to understand all that.他 太年轻了，不能理解这件事 五、动词不定式作宾语补足语 动词不定式作宾语补足语是动词不定式用法的 一个重点，要注意以下三种情况: • 1.作动词ask, like, tell等的宾语补足语时，动 词不定式符号to不可以省略。例如:He asked me to talk about English study.他请我谈谈 英语学习
Practice： 1、You should know better than___your little sister at home by herself. A.to leave B.leaving C.have left D.left Solution:此处than作连词，其后引导的不定式短语作know的宾语 2、He made a long speech___his ignorance of the subject. A.only showing B.only showed C.only to show D.only as to show Solution:此题考查only to do的用法。“only to do” 结构常用作句子的结果状语，表示未曾预料到的令人懊丧的结 果。 相关链接： 一、表示结果的”only to do”结构可以改为由and或but连接的并 列句，但仍然表示结果之意。例如： 1。I ran to the school，only to be informed that I wasn‟t admitted by Pecking University=I ran to the school and was informed that I wasn‟t admitted by Pecking University。
• 2.作使役动词let, have, make以及感官动词feel, hear, see, watch等的宾语补足语时,动词不定式 符号to要省略（但是被动语态时to不能省略）。 例如: The teacher made him say the word like this. 老师让他像这样说这个单词 • 3.作动词help的宾语补足语时,动词不定式符号to 可以带，也可以不带。例如:Could you help me (to) carry the heavy box？你能帮我搬这个 重箱子吗？
Attention: get作"使,让,叫某人做某事"时,要用get sb. to do s t h. 结构.例如: Mother got Tom to buy a pack of sugar 2.两个或两个以上的动词不定式由连词and \or \than \but 连接时,从第二个不定式起,往往省略不定式符号to.但如 果强调对比之意时不省略.例如 (1)She 'd like to take off her coat and have a break. (2)The students are taught to read,write and do many other things. (3)I t 's more difficult to do than to say .(强调语意前 后对比) (4)The teacher came not to punish you but to help you.(强调语意前后对比) (5)I wondered whether to study or to work.(强调语 意前后对比)
b) 省略动词不定式符号to的情况 1.动词不定式作感官动词feel \see \notice \watch \find \hear \listen to \observe和使役动词have \make \let等的宾语补足语时,动词不定式符号to 省略.如果这些动词用于被动语态,其后的动词不 定式符号to不能省略(但let除外).例如: (1)We often hear him sing the song at home . (=He is often heard to sing the song at home.) (2)The y knew her very well.They had seen her grow up from childhood. (=They knew her very well.She was seen to grow up from childhood.)
2.不定式作宾语补足语时,省略to后的动词部分,即 用to代替整个不定式.例如: (1)The boy wanted to ride his bicycle in the street but his mother told him not to. (2)You'd better finish the job on time if he ordered you to. 3.在一些情态动词或助动词ought to \have to \used to \be able to后.例如: (1)-Must I go now -No.You don 't have to. (2)-Are you planning to see your grandfather -No.But I ought to
二、带逻辑主语的动词不定式短语： 为了特别说明动词不定式短语动作的发出者，动 词不定式可以带有自己的逻辑主语，构成方法 是： for + 逻辑主语 + 不定式。（注意：逻辑主 语用宾格形式， for 本身无实际意义，它只表明 后面的主语从逻辑上分析是不定式的主语。） It„s necessary for us to help each other. 我们互相帮忙是必要的 There is much work for me to finish 有许多工作要我去完成
3.不定式作表语,用来解释主语或主语从句中do的 精确含义时,往往可以省略动词不定式符号to.例 如: (1)The first things he did was go up to her trainer and thank her for all her help during her training. (2)What we want to do now is lie down and rest. (3)What a dictionary does is help the students to find out the meaning and the usage of new words
4.在why或why not引起的表示建议或责问的省略问句中. 例如: (1)Why get so excited (2)Why not join us,Tom 12月专四模拟题 Since you are free,why__it now? A.don‟t B.dosen‟t C. not do D.do not 5.在一些类似情态动词词组had better \would rather \would sooner\would （just） as soon（宁愿） \may/might as well\had best \rather than \can‟t but \can‟t help but（不由得不）等之后.例如: (1)In China it is important to invest in education rather than increase personal wages. (2)Jack would rather read than talk. (3)You'd better put on more clothes,or you'll catch a bad cold. (4)She dares to go to the lonely island by herself.I can 't but admire her bravery.
动词不定式短语的两种主要形式
一、带疑问词的动词不定式短语： who, what, which, when, where, how, why 以及whether等疑问词加to do可构成不定式 短语，在句中可作主语、宾语、宾语补足语、 表语等。eg： When to start has not been decided. (主 语） I don’t know what to do. （宾语） He can tell you where to get the book. （宾语补足语） The question is who(m) to ask. （表语）
• I find it useful to learn English well.我发现 学好英语很有用 • 三、动词不定式作定语 不定式作定语，要放在它所修饰的名词或 代词的后面。例如: I have nothing to say on this question.对这个问题我无可奉告 四、动词不定式作状语 动词不定式及其短语具有副词的特性，可在 句中用作状语。 1.放在句首也可以放在句尾表示目的 例如: He stopped to have a rest.他停下来 休息
• 2. He survived the crash only to die in the desert. 相当于： He survived the crash but died in the desert. 飞机坠毁时 他幸免遇难，但却死在了沙漠里。 • 二、 “ only ＋不定式”结构也可以表示目的。例如： She didn„t call you only not to trouble you. 她没给你打电 话是不想给你添麻烦。 三、“ if only to do... ”表示语气上的转折，常译为：“即使只 是为了……”。例如： I would rather make a journey to Emei Mountain, if only to enjoy some fresh air. 我宁愿去峨眉山，就算只是为了呼 吸一点新鲜空气也值。 四、“ have only to do sth. ”结构意为“只要……就行” 例 如：You have only to finish your own job. 你只要完成你 的那份工作就行了。 五、 “ have only to... to... ”结构表示“只要……就” 例如： You have only to call us in 8 hours to get a set of software worth of 60 dollars. 只要在 8 小时之内给我们打 电话，你就会获得一套价值 60 美元的软件。