在英语语法中，动词不定式（Infinitive）是一种非谓语动词形式，由动词的基本形式加上“to”构成。不定式可以起到名词、形容词或副词的作用，并能作为句子的主语、宾语、宾语补足语等。
动词不定式有两种形式：带有“to”的to-infinitive和不带“to”的bare infinitive。其中，to-infinitive常用于表示目的、原因、结果、意图、需求等，也常用于某些动词后作宾语。bare infinitive则用于情态动词、感官动词、助动词等后面。
| 作为主语 |
- To travel is my dream.
- To learn a new language takes time.
|
| 作为宾语 |
- She wants to eat pizza for dinner.
- He refused to help us.
|
| 宾语补足语 |
- I believe her to be honest.
- They considered him to be the best candidate.
|
| 形容词补足语 |
- I am happy to see you.
- She was excited to receive the award.
|
| 副词 |
- He ran to catch the bus.
- She went to the store to buy groceries.
|
还有一些动词后面用不定式作宾语时，其后通常必须有一名词或代词。这类动词有 allow，advise，help， teach，tell，request 等。
- We were not allowed to see the picture. 被动语态
- I asked him to lend me twenty pounds.ask sb. to do sth.
- I want to speak to John.want to do sth.
- I want you to speak to John. want sb. to do sth.
| Would you like to do sth.? |
Would you like to stay and have dinner?你愿意留下来吃晚餐吗？ |
| I’d like sb. to do sth. |
I'd like you to meet him.我想让你见见他。 |
| I’d like to do sth. |
I'd like to learn a new language.我想学习一门新的语言。 |
hope 一定不能说 hope sb. to do sth.
hope 觉得某事可能发生或者通过自己努力可以让其发生I hope that you have a good time.；wish 觉得某事不可能或者难以实现（往往是幻想或遗憾）I wish I had studied harder.
| hope to do |
hope (that) + 从句 |
| We hope to arrive around two.我们希望能在两点钟左右到达。 |
I hope you are right.我希望你是对的。 |
动词 + to do sth. 主语自己做某事
| want / wish / ask to do 想要/希望/要求做 |
She asks to speak with the manager directly. 她要求直接与经理谈话。 |
| aim / fail / long to do 打算/未能/渴望做 |
The project aims to provide clean water for everyone. 该项目旨在为每个人提供清洁饮水。 |
| beg / care / agree to do 请求/想要/同意做 |
Would you care to join us for dinner tonight? 今晚你想和我们一起吃晚饭吗？ |
| offer / fear / help to do 主动提出/害怕/帮助做 |
He offered to carry her heavy bags to the car. 他主动提出帮她把沉重的包拎到车上。 |
| hope / learn / plan to do 希望/学习/计划做 |
I hope to travel around the world next year. 我希望明年能环球旅行。 |
| choose / decide / expect to do 决定/决定/期待做 |
We expect to finish the report by Friday. 我们预计周五前能完成报告。 |
| pretend / arrange / promise / demand to do 假装/安排/答应/要求做 |
The protesters demand to see the mayor. 抗议者要求见市长。 |
动词 + sb. + to do sth. 要/让别人做某事
| warn / wish / cause sb. to do 警告/希望/导致某人做 |
The ice caused the car to slide off the road. 冰导致汽车滑出了路面。 |
| drive / request / remind sb. to do 驱使/要求/提醒某人做 |
Hunger drove him to steal a loaf of bread. 饥饿驱使他偷了一块面包。 |
| trouble / mean / intend sb. to do 麻烦/打算要/打算要某人做 |
I never meant you to find out this way. 我从没打算让你以这种方式发现真相。 |
