此外，這種不定式結(jié)構(gòu)還可作主語(yǔ)，表語(yǔ)，和介詞賓語(yǔ)等。
How to live a happy life is a difficult question to answer. 怎樣過(guò)幸福生活是個(gè)很難回答的問(wèn)題
The question is whom to choose for the position. 問(wèn)題是這個(gè)位置選誰(shuí)。
That was a discussion about how to increase their strength. 那是一次關(guān)于怎樣增強(qiáng)他們力量的討論。
He said nothing about what to do with her. 關(guān)于拿她怎么辦，他啥也沒(méi)說(shuō)。
She asked my suggestion just now about where to go for her holidays. 關(guān)于去哪里度假，她剛才征求了我的意見(jiàn)。
3、有些動(dòng)詞需要不定式作賓語(yǔ)補(bǔ)足語(yǔ)。這種動(dòng)詞常見(jiàn)的有：ask請(qǐng)求，advise勸告，allow允許，beg乞求，believe相信，call on號(hào)召，cause促使，compel強(qiáng)迫，command指揮，direct指導(dǎo)，enable使…能夠，encourage鼓勵(lì)，expect期望，feel覺(jué)得，force迫使，get使得，hate不喜歡，have使，hear聽(tīng)見(jiàn)，help幫助，inspire鼓舞，intend 打算,invite邀請(qǐng),instruct指示，know知道，lead引導(dǎo)，let讓?zhuān)琹ike喜歡，listen to 聽(tīng)，look at看，make 使得, notice注意到, observe觀察，order命令，permit允許，persuade說(shuō)服，prefer更喜歡，press施加壓力，remind提醒，request請(qǐng)求，teach教，tell告訴，urge敦促，want 想要，warn警告，wish希望，等等。
I asked my mother to buy a new bike for me. 我請(qǐng)求媽媽給我買(mǎi)輛新自行車(chē)。
Tony knew his girl friend to be a shy college student. 托尼知道他的女朋友是一個(gè)害羞的大學(xué)生。
They helped you to get on the bus, didn’t they? 他們幫你上了汽車(chē)， 是嗎?
4、有些動(dòng)詞要求省掉to的不定式作賓語(yǔ)補(bǔ)語(yǔ)。這樣的動(dòng)詞有：feel覺(jué)得，have使，hear聽(tīng)見(jiàn)，help幫助，let讓?zhuān)琹isten to 聽(tīng)，look at看，make使，notice 注意，see看見(jiàn)，observe 觀察，watch觀看 等，一類(lèi)是感官動(dòng)詞，一類(lèi)是使役動(dòng)詞。
A policeman saw the accident happen. 一位警察看見(jiàn)事故發(fā)生。
We listened to her talk about her experience abroad. 我們聽(tīng)她講國(guó)外的經(jīng)歷。
We’d be glad to have you work with us. 我們會(huì)很高興有你和我們一起工作。
上述help后面的不定式省掉to與保留to都可以。在被動(dòng)語(yǔ)態(tài)中，上述動(dòng)詞后面的不定式要把省去的to還原。
I heard the dog come in. 我聽(tīng)見(jiàn)那條狗進(jìn)來(lái)。
=The dog was heard to come in. 有人聽(tīng)見(jiàn)那條狗進(jìn)來(lái)。
I saw her go out by bike. 我看見(jiàn)她騎著自行車(chē)出去了。
=She was seen to go out by bike. 有人看見(jiàn)她騎著自行車(chē)出去了。
Can I help (to) lift this heavy box? 我可以幫著搬起這個(gè)沉重的箱子嗎?
You may as well help me (to)get things straight. 你不妨幫我把東西整理好。
She helped the old woman (to) cross the street. 他幫助那位老婦人過(guò)街
在had better()，would rather(寧愿)，would sooner(寧愿)，would (just) as soon(寧愿)，cannot but(不能不，不由得不)，cannot help but(不能不，不由得不)等成語(yǔ)后面也跟不帶to的不定式：
He would rather listen to others than talk himself. 他寧愿聽(tīng)別人也不愿自己說(shuō)。
He would sooner play than work. 他寧愿玩也不愿干活。
You had better go away right now. 你立即就走。
I would rather take this method. 我倒愿意采取這個(gè)辦法。
I’d rather walk than take a bus. 我寧可走也不愿坐公共汽車(chē)。
She’d rather die than lose the children. 她寧可死也不愿失去孩子們。
I’d rather not have eggs and bacon for breakfast.
She’d sooner stay at home.
I would as soon do it by myself.
I would just as soon stay as go. 我寧愿住下也不愿去。
How to live a happy life is a difficult question to answer. 怎樣過(guò)幸福生活是個(gè)很難回答的問(wèn)題
The question is whom to choose for the position. 問(wèn)題是這個(gè)位置選誰(shuí)。
That was a discussion about how to increase their strength. 那是一次關(guān)于怎樣增強(qiáng)他們力量的討論。
He said nothing about what to do with her. 關(guān)于拿她怎么辦，他啥也沒(méi)說(shuō)。
She asked my suggestion just now about where to go for her holidays. 關(guān)于去哪里度假，她剛才征求了我的意見(jiàn)。
3、有些動(dòng)詞需要不定式作賓語(yǔ)補(bǔ)足語(yǔ)。這種動(dòng)詞常見(jiàn)的有：ask請(qǐng)求，advise勸告，allow允許，beg乞求，believe相信，call on號(hào)召，cause促使，compel強(qiáng)迫，command指揮，direct指導(dǎo)，enable使…能夠，encourage鼓勵(lì)，expect期望，feel覺(jué)得，force迫使，get使得，hate不喜歡，have使，hear聽(tīng)見(jiàn)，help幫助，inspire鼓舞，intend 打算,invite邀請(qǐng),instruct指示，know知道，lead引導(dǎo)，let讓?zhuān)琹ike喜歡，listen to 聽(tīng)，look at看，make 使得, notice注意到, observe觀察，order命令，permit允許，persuade說(shuō)服，prefer更喜歡，press施加壓力，remind提醒，request請(qǐng)求，teach教，tell告訴，urge敦促，want 想要，warn警告，wish希望，等等。
I asked my mother to buy a new bike for me. 我請(qǐng)求媽媽給我買(mǎi)輛新自行車(chē)。
Tony knew his girl friend to be a shy college student. 托尼知道他的女朋友是一個(gè)害羞的大學(xué)生。
They helped you to get on the bus, didn’t they? 他們幫你上了汽車(chē)， 是嗎?
4、有些動(dòng)詞要求省掉to的不定式作賓語(yǔ)補(bǔ)語(yǔ)。這樣的動(dòng)詞有：feel覺(jué)得，have使，hear聽(tīng)見(jiàn)，help幫助，let讓?zhuān)琹isten to 聽(tīng)，look at看，make使，notice 注意，see看見(jiàn)，observe 觀察，watch觀看 等，一類(lèi)是感官動(dòng)詞，一類(lèi)是使役動(dòng)詞。
A policeman saw the accident happen. 一位警察看見(jiàn)事故發(fā)生。
We listened to her talk about her experience abroad. 我們聽(tīng)她講國(guó)外的經(jīng)歷。
We’d be glad to have you work with us. 我們會(huì)很高興有你和我們一起工作。
上述help后面的不定式省掉to與保留to都可以。在被動(dòng)語(yǔ)態(tài)中，上述動(dòng)詞后面的不定式要把省去的to還原。
I heard the dog come in. 我聽(tīng)見(jiàn)那條狗進(jìn)來(lái)。
=The dog was heard to come in. 有人聽(tīng)見(jiàn)那條狗進(jìn)來(lái)。
I saw her go out by bike. 我看見(jiàn)她騎著自行車(chē)出去了。
=She was seen to go out by bike. 有人看見(jiàn)她騎著自行車(chē)出去了。
Can I help (to) lift this heavy box? 我可以幫著搬起這個(gè)沉重的箱子嗎?
You may as well help me (to)get things straight. 你不妨幫我把東西整理好。
She helped the old woman (to) cross the street. 他幫助那位老婦人過(guò)街
在had better()，would rather(寧愿)，would sooner(寧愿)，would (just) as soon(寧愿)，cannot but(不能不，不由得不)，cannot help but(不能不，不由得不)等成語(yǔ)后面也跟不帶to的不定式：
He would rather listen to others than talk himself. 他寧愿聽(tīng)別人也不愿自己說(shuō)。
He would sooner play than work. 他寧愿玩也不愿干活。
You had better go away right now. 你立即就走。
I would rather take this method. 我倒愿意采取這個(gè)辦法。
I’d rather walk than take a bus. 我寧可走也不愿坐公共汽車(chē)。
She’d rather die than lose the children. 她寧可死也不愿失去孩子們。
I’d rather not have eggs and bacon for breakfast.
She’d sooner stay at home.
I would as soon do it by myself.
I would just as soon stay as go. 我寧愿住下也不愿去。