英语语法讲座系列之八 Infinitive 不定式 -- by Dana Ni

I. 构成与特征 不定式（Infinitive） 动词不定式是动词的一种非限定形式， 由“to+动词原形”构成，在句中起名词、形容词或副词的作用，同时也保留动词的一些特征，可以带宾语或状语。

II. 功能 作主语 作宾语 作宾语补足语 作表语 作定语 作状语

1.作主语 To persevere means victory! 坚持就是胜利！ For him to admit his mistake is not easy. 要他承认错误不是容易的。（带逻辑主语） Never to have made any mistake is impossible. 从不犯错误是不可能的。（带副词） How to make our life longer is a big problem. 怎样使我们活得更长久是个大问题。（带关系副词）

1.作主语 但在很多情况下，特别是在口语中，我们常用代词 it 代替作形式主语（但不可用 that 作形式主语）。不定式则移到谓语之后，这样使句子显得比较平稳。

T 2.F e.g. 1. It is very difficult to drive in the mountains. 2. That is very difficult to drive in the mountains. 2. It is very difficult to drive in the mountains. 3.It is not an easy thing to master a language. To master a language is not an easy thing.

Note ： (1)不定式作主语时，在很多情况下都可用动名词代替 e.g. Hesitating means failure. 但作主语的不定式是固定的说法或表示较强烈对比或某些具体情况等，通常不用动名词替代。 e.g. To teach is to learn. （对比） To finish this job in one day is impossible. (某次具体情况)

1.作主语 （2）有时候，作主语的不定式相当于一个条件从句。 e.g.To love others is to be loved. If you love others, you will be loved by others. back

2.作宾语 He offered to help us . 他提出要帮助我们。 Children love to listen to fairy tales. 孩子们喜欢听童话故事。 能以不定式作宾语的动词: try, ask, offer, want, like, wish, hate, prefer, continue, manage, start, promise, forget, mean, intend, begin, agree, care, choose 等。

他忘记给儿子买过生日礼物了。（做过忘记了) 既可跟不定式又可跟动名词的动词 1）意义不变的有： begin,continue,prefer,start,hate,like, etc. e.g.He started to do/doing his experiment after his dinner. 2) 意义不同的有： stop,remember,forget,regret,try,mean,go on etc. e.g.He forgot to buy a present for his son. He forgot buying a present for his son. 他忘记给儿子买生日礼物。（没有做） 他忘记给儿子买过生日礼物了。（做过忘记了)

(1) 动词+ how / what / where / which / when/why + 不定式 2.作宾语 Note: (1) 动词+ how / what / where / which / when/why + 不定式 这类动词中最常用的是： ask, decide, know, tell, teach, find out, learn etc.

We must decide whether to go or stay. e.g. We must decide whether to go or stay. No one could tell me where to get the book. She couldn't think what to say. They will teach us how to repair farm tools. I didn't know when to switch the machine off. I showed her which button to press.

(2)另外，在某些复合宾语中，常用一个it 代表不定式，而把不定式放到后面. e.g. They found it impossible to get everything ready in time. She thought it unnecessary to argue with him about it. I consider it better not to go.

3.作宾语补足语 I wrote him to come at once. 我写信要他马上过来。 They encouraged her to try again . 他们鼓励她再试一次。

3.作宾语补足语 下列表示“指示、愿望、感觉”等的动词（短语）后常用不定式做宾语补足语： ask 要求 allow 允许 advise 劝告 tell 告诉 wish 希望 want 想要 expect 期望 encourage 鼓励 intend 打算 permit 允许 remind 提醒 request 要求

(1)hope、demand、suggest等动词后面不能接动词不定式作宾语补足语。 Note : (1)hope、demand、suggest等动词后面不能接动词不定式作宾语补足语。 He hoped his sister to lend him a hand. He hoped that his sister would lend him a hand. I suggested that he not go there alone. I suggested him not to go there alone.

3.作宾语补足语 1. I know this to be a fact. (2) feel，understand，suppose，know， find，believe，consider，think 等动词后的宾语补足语多是 to be 形式。 e.g. 1. I know this to be a fact. 2. He doesn't consider that to be true.

4.作表语 最重要的是把理论变为实际。 The problem is to find a solution. 问题是得找出一个解决办法。 The most important thing is to put theory into practice. 最重要的是把理论变为实际。

Note： 不定式作表语，可用主动形式表示被动意义。 她应该受到责备。 A great deal is yet to do. e.g. She is to blame. 她应该受到责备。 A great deal is yet to do. 还有许多事 情要做。

5.作定语 （1）动词不定式与其所修饰的词之间往往有动宾关系，如果这个不定式是不及物动词，它后面就应该有必要的介词。

Do you have anything more to___ (say)? I want to get something to ___(read) during the vacation. read She is a very nice person to ____(work). work with There is nothing to____( worry). worry about

Thank you for giving me the chance to make the speech. (2)有些名词后常跟不定式作定语 time 时间 chance 机会 way 方法 reason 理由 effort 努力 right 权利 e.g. Thank you for giving me the chance to make the speech. 谢谢你给我发言的机会。 Is that the best way to solve the problem? 这是解决问题的最好办法吗？

5.作定语 The plans to be made are of vital importance. （3）不定式可以修饰作主语的名词，相当于 一 个定语从句，表明动作即将发生。 e.g. The plans to be made are of vital importance. 要制定的计划至关重要。 The conference to take place next month is bound to be a great success. 下个月的会议一定很成功。

6.作状语 不定式作状语的情况很多，可以表示目的，结果或原因等。 （1）表示目的 不定式也常用在so as (to) 或 in order(to) 后,与它合起来作状语用, 否定式 in order not+ 不定式或 so as not +不定式。

6.作状语 The whole family went to beach to spend their weekend. 全家人去海边度周末。 To save the child, he laid down his life. 他为了抢救那个儿童而献出了自己的生命。 Let’s hurry so as not to be late for the meeting. 咱们快点走，免得开会迟到。 6.作状语

6.作状语 (3)表原因 (2)表结果 He left, never to return. 他走了,再也没有回来。 She lived to be 100 . 她活到一百岁。 (3)表原因 We jumped with joy to hear the news. 我们听到这个消息后高兴得跳了起来。

6.作状语 (4)表说话人的态度，对整个句子进行解释，在句中作独立成分。 e.g. 1)To tell you the truth, I am not in favor of your plan. 说实话，我不赞成你的计划。 2) To be frank, we don’t trust him. 坦白地说，我们不信任他。

6.作状语 so… as to 引导的是结果状语从句，so 后面跟形容词或副词，表示“到某种程度以致…”。 1. so as to 引导的是目的状语从句，相当于in order to , 表示“以便”； so… as to 引导的是结果状语从句，so 后面跟形容词或副词，表示“到某种程度以致…”。 2. so as to 前面可用逗号，而so … as to 则不可。 5)so as to 不同于so … as to

e.g The test questions are kept secret, so as to prevent cheating . 考题保密，以防作弊。 露丝不会那么粗心，以致于把钢笔忘了带。(=so …that) The test questions are kept secret, so as to prevent cheating . Rose wouldn’t be so careless as to forget her pen .

Ⅲ.动词不定式的时态和语态意义 不定式有一般、进行、完成和完成进行四种时态变化形式。一般式和完成式有被动语态变化形式。

时态 主动语态 被动语态 一般式 to do to be done 进行式 to be doing 完成式 to have done to have been done 完成进行式 to have been doing

1.动词不定式的时态意义 1)不定式的一般式 不定式的一般式表示的动作与谓语动词的 动作是同时发生的或是在其后发生的。 e.g.Thousands of young people are learning to ski. 数以千计的年轻人在学习滑雪。（同时） They invited us to go there this summer. 他们邀请我们今年夏天到那儿去。（未来）

2)不定式的进行式 不定式的进行式表示的动作与谓语动词的动作是同时的，而且是正在进行着的。 A.They are said to be building another bridge across the river. 据说他们正在这条河上修另一座大桥。 B.They seem to be getting along quite well. 他们似乎相处得很好。

不定式所表示的动作，在谓语所表示的动作（状态）之前发生。 3) 不定式的完成式 不定式所表示的动作，在谓语所表示的动作（状态）之前发生。 A.I am glad to have seen your mother. (=I am glad I have seen you mother.) 我很高兴，见到你妈妈。 B.The enemy was reported to have surrendered. (=It was reported that the enemy had surrendered.) 据报道敌人投降了。

4)不定式的完成进行式 表示动作在谓语动词的动作之前发生，而且一直进行着。 A.He was happy to have been staying with his uncle. 他很高兴一直跟他叔叔住在一起。 B.The struggle was known to have been going on for over twenty years. 据悉这个斗争已进行二十多年了。

(1)如果逻辑主语是动作的执行者，不定式用主动式,如果逻辑主语是动作的承受者，不定式用被动式。比较： 2.  动词不定式的被动语态 不定式被动式的逻辑主语 (1)如果逻辑主语是动作的执行者，不定式用主动式,如果逻辑主语是动作的承受者，不定式用被动式。比较： A. The doctor recommended him to air the room. 医生建议他让房间透透气。（主动式） B.The doctor recommended the room to be aired. 医生建议让房间透透气。（被动式）

(2) 在“名词（代词）+be+easy (difficult,fit) + 不定式”结构中，有时尽管句中主语是动作的承受者，不定式在意义上是被动的，形式上却是主动的。 A.The book is difficult to read. 这本书很难读懂。 B.The path is easy to find. 这条路很好找。

(3)something、little、what、a great deal 等作句子的主语，表语为 to do 时，多用主动语态表示被动意义。 e.g. A great deal of work remains to do . What is to do tomorrow?

Ⅳ.不带to的动词不定式 1.在助动词和情态动词 “do,will,shall,would,should,can,may,must etc.”之后： e.g. You must do as you’re told. He will probably object.

Ⅳ.不带to的动词不定式 2.在“使役动词 let, make, have etc.+宾语”之后 e.g.We can’t let this go on. He won’t have us criticize his work. 当使役动词为被动语态时，不带 to 不定式转为带to不定式： e.g.John made her tell him everything. She was made to tell him everything.

Ⅳ.不带to的动词不定式 3.在“感觉see,hear,observe,notice,feel ,watch+宾语“之后： e.g.I watched him eat his breakfast. We feel the house shake. 当感觉动词为被动时态时，不带to不定式转为带to不定式： e.g.They saw him enter the building. He was seen to enter the building.

Ⅳ.不带to的动词不定式 4.在help（或help+宾语）之后，既可以用不带to不定式，也可用带to 不定式。 e.g. I’ll help you (to) solve it. 5.在介词except/but之后（如果except/but之前有动词“do”的某种形式，其后通常用不带to不定式，否则带to。 e.g.They did nothing except work. There’s no choice but to wait.

Ⅳ.不带to的动词不定式 6. 在“why/why not……?”之后 e.g.Why spend such a lot of money? Why not wait for a couple of days? 7.在“had better, had best ,would rather, would rather…than, would sooner, cannot but ,would sooner…than, do nothing but 等结构后面。

Ⅳ.不带to的动词不定式 You’d better remain where you are. e.g. You’d better remain where you are. 你最好待在你现在待的这个地方。 I would (had) rather not see him. 我宁愿不去见他。 They would rather try and fail than give up the plan. 他们宁愿尝试不成功也不愿放弃这个计划。

Ⅳ.不带to的动词不定式 8.在go, come 和 run 后可省略 to，直接用另一个动词，多用于表示命令，建议,请求或意愿的句子中。 e.g.Come have a drink with us. (=Come to have…) I’ll go see my sister.(=go to see…) Let’s go hear a concert.

Ⅳ.不带to的动词不定式 9.rather than 或sooner than 位于句首时，其后的动词不用to。 e.g. 1.Sooner than run the risk of losing more money, he agreed to the term. 2.Rather than travel by air, he preferred a train on his tour.

Ⅳ.不带to的动词不定式 10.为避免重复，不定式可省略去to。 e.g. He was at a loss as to what to think and say. 但是如果两个不定式表示对照或对比，则不可省去to。 e.g. To die or not to die -- that is the question. He hasn’t decided whether to go home or to stay at school during the vacation.

go change to give up eat stay We had better (go) there by air. She could do nothing but (change) her name under the circumstances. He was made (give up) his dream. I watch him (eat) his breakfast. In fact ,she would rather leave for San Francisco than (stay) in Los Angeles. go change to give up eat stay

Ⅴ.不定式符号to 和介词to 的辨别问题 英语中有相当数量的常用短语，其最后一个词 是 to ；to 既可以是介词，也可以是不定式符号。作为介词，to后面接名词或动名词; 作为不定式符号，后面须接动词原形，不可混淆。下面提供七种类型含介词to的搭配。

含介词to的搭配 1. 动词+介词to agree to (同意)，admit to（承认）， attend to（注意、照顾）.come to（到达，涉及到），contribute to (承认)，object to （反对），refer to (提及)

含介词to的搭配 2.动词+名词/代词+介词to attribute…to（归因于), apply…to（致力于）, accustom…to (使习惯于)，confine…to (限于…范围内)，dedicate…to（奉献），prefer…to （喜欢），owe…to （归功于）

含介词to的搭配 3. 动词+ed 分词+介词to be accustomed to （惯于）,be devoted to （致力于），be used to （习惯于，适应于）， be reduced to （使变小），be reconciled to（甘心于，顺从） 等。

含介词to的搭配 4. 动词+副词小品词+介词 to get down to （开始认真做某事），look forward to （盼望），get near to （几乎，接近于，face up to （勇敢地面对）等。 5. 形容词+介词to similar to （类似）,loyal to （忠于）， deaf to（不愿意听），superior to （优于、胜过），sensitive to （敏感），preferable to （较合人意）等。

含介词to的搭配 6. 名词+介词to objection to（反对）,answer to（回答、答复）,limit to （限度），aid to (辅助) indifference to （不关心），key to （解答，关键）等。 7. 以介词to 结尾的复杂介词 according to（根据，按照）,as to（关于）,owing to （因为，由于），thanks to （由于，多亏），in addition to （除… 之外）等。

You must accustom yourself to ( get ) up early. We are looking forward to (see) you again. He used to (smoke ) a pipe. He was reduced to (beg) for food. She is working hard to (earn) money. getting seeing smoke begging earn

Good Luck! Good Bye!