2．不定式作形容词的宾语，和句子主语构成逻辑上的动宾关系时。

　 The book is difficult to understand. 这本书很难理解。

　 The chair is comfortable to sit on. 这把椅子坐起来很舒服。

1．不定式做后置定语，和被修饰的名词或代词构成逻辑上的动宾关系，但又和该句主语构成逻辑上的主谓关系时。

　 Do you have anything to say on this question 针对这个问题你有什么要说的吗？

　 He is a pleasant person to work with. 他是一个与其合作起来令人感到愉快的人。

2．表示计划或安排

　 We are to begin the work next month. 我们安排下一个月开始这项工作。

　 What's to be done next 下一步该怎么办？

　 C．疑问词 + 不定式结构

　 疑问词who, what, which, when, where, how, why后加动词不定式构成不定式短语，它在句中可作主语、宾语和表语。

　 I don't know whether to go to the meeting or not. 我不知道要不要去开会。

　 The problem was how to get rid of the waste thrown by the passengers. 问题是如何处理乘客们丢弃的垃圾。

　 When to visit the Palace Museum has not been decided yet. 何时参观故宫博物院还没有决定。

　 D．withwithout + 名词 + 不定式结构

　 “withwithout + 名词 + 不定式”结构在句子中通常起状语的作用。

　 With so much work to do, I shall not be able to go to the cinema with you. 有这么多工作要做，我不能和你去看电影了。

　 With him to stay in the house, I feel quite safe. 有他住在家里，我感到十分安全。

　 Without anything to eat, he died of hunger. 由于没有东西吃，他饿死了。

　 E．It is + 形容词 + forof sb + to do 结构

　 在“It is +形容词+ of sb +不定式”结构中，形容词往往表示人物的性格和特征，如kind, silly, good, unwise, clever, wrong, right, foolish, stupid, careless, rude, impolite, bold, thoughtful, honest, bad, sensible, naughty等。在“It is +形容词+for sb +不定式”结构中，形容词通常表示事物的性质，如important, possible, impossible, necessary, difficult, hard, reasonable等。

　 It's kind of you to think so much of us.　 难为你这么为我们着想。(= You are kind to think so much of us.)

　 How careless it is of him to break such a valuable vase! 他真不小心，把如此贵重的花瓶打破了。

　 It is easy for me to see through his trick. 我很容易看穿他的鬼把戏。(=For me to see through his trick is easy.)

　 It is hard for him to get rid of his bad habits. 他很难改掉自己的坏习惯。

　 比较：

　 It is good lf you to help me with my English.　 你真好，帮助我学英语。(强调you 的特征＝You are good to help me.)

　 It is good for you to give up smoking.　 戒烟对你有好处。(强调的是give up smoking 这一行为＝Fof you to give up smoking is good.)

　 F．分裂不定式

　 动词不定式to do通常是不拆开的，但偶尔也可在不定式符号to和动词原形之间插入一个副词，构成分裂不定式。

　 He was too ill to completely carry out that program. 他病得太重，不能完成那个项目。

　 He has made up his mind to once more try this method.　 他已经下定决心再试试这个方法。

　 G．用作独立成分的不定式

　 有一些不定式短语可以作状语修饰整个句子，也可被称为插入语。

　 To be honest, we are not sure to find the girl in the forest. 说老实话，我们不能确保在森林里能找到那个女孩。

　 To be frank, I don't agree with what you said.　 坦率地说，我不同意你说的话。

　 必背：用作独立成分的不定式

　 to tell you the truth 说老实话

　 to be frank　 坦率地说

　 to begin with 首先

　 to be brief 简言之

　 to make a long story short 长话短说

　 to be exact 精确地说

　 to say nothing of 姑且不说

　 to conclude 总而言之

　 to be sure 诚然，固然

　 to do him justice 说句对他公道的话

　 so to speak 可以这么说

　 H．用主动式表示被动含义的不定式

　 动词不定式在句中究竟用主动还是被动，有时比较复杂，主要有下面几种情况：

A．　 不定式的复合结构

　 动词不定式的逻辑主语(即不定式动作的执行者)通常是句子的主语或宾语。如果不定式的逻辑主语不是句子的主语，此时一般用“for + 名词(代词)+ 不定式”来构成不定式的复合结构，这种复合结构在句中可以做主语、宾语、表语、状语、定语。

　 This box is too heavy for the little boy to carry.　 这个箱子让这个小男孩来搬太重了。

　 That's for you to decide. 那个由你来决定。

　 He stood aside for me to pass. 他站到一边让我通过。

　 I have some books for you to read. 我有几本书送给你读

。

　 B．be + 不定式结构

　 “be + 不定式”结构可以表示将来发生的动作，常有以下两种情况：

1．表示命令和指示

　 The room is to be locked. 这房间要上锁。

　 You are not to stand here. 你不能站在这里。

4．表示条件

　 A man would be blind not to see that. 一个人如果看不到这点，那他就是瞎子。

　 How can you catch the train to start so late 这么晚才动身，你怎么能赶上火车？

动词不定式(二)

3．表示原因

　 I was a fool not to listen to you at that time.　 我当时不听你的话，真是傻瓜。

　 She wept to find him in such a difficult situation. 看到他处于这么困难的情形，她哭了。

2．表示结果

　 He got to the station only to find the train had gone. 他赶到车站，发现火车已经开走了。

　 What have I said to make you so angry 我说了什么话使你气成这样？

　 After the meeting, they parted, never to see each other again. 散会后，他们分手了，从此再也没有见面。

　 必背：不定式表示结果常见于下列句型。

　 1) so ... as to do

　 Would you be so kind as to lend me your bicycle 把你的自行车借给我好吗？

　 2) such ... as to do

　 We are not such fools as to believe him. 我们还没蠢到竟会相信他。

　 3) enough to do

　 He didn't run fast enough to catch the train.　 他跑得不够快, 没赶上火车。

　 4) only to do

　 He lifted a rock only to drop it on his own feet. 他搬起石头砸自己的脚。

　 5) too ... to do

　 His eyesight is too poor to read such small letters. 她的视力太差了，不能看这么小的字。

　 注意：too...to...结构中的形容词如果是eager, pleased, happy, ready等，动词不定式不表示结果，也没有否定的意思。

　 The boy was too eager to get a geography book. 那个男孩非常急切地想要得到一本地理书。

　 He is too anxious to know the examination results. 他很急切地想知道考试结果。

1．表示目的

　 I'm saving up to buy a computer. 我在存钱买电脑。

　 To save the child, he laid down his life. 为了救那个孩子，他献出了生命。

　 注意：有时为了强调或突出这种目的，也可以用in order (not) to do,和so as (not) to do结构(so as to do不可以置于句首)。

　 He shouted and waved in order to be noticed. 为了吸引注意，他又嚷嚷又挥手。

　 I'll write down his telephone number so as not to forget it. 我要把他的电话号码记下来，以防忘记。

4．修饰关系

　 Now it is time to begin our class. 现在是上课的时间了。

　 I need somewhere to take a nap. 我需要一个地方打个盹。

　 Is that the way to open the can 那就是打开罐头的方法吗？

　 F． 动词不定式作状语

　 不定式作状语可以表示行为的目的、结果、原因、条件等。

3．同位关系

　 He broke his promise to write to his parents regularly. 他没有遵守诺言定期给他父母亲写信。

　 We students should have the courage to face any difficulty. 我们学生应该有勇气面对任何困难。

　 I have no wish to quarrel with you. 我不想和你吵架。