4)"wh word＋不定式"結(jié)構(gòu)不定式前加一個疑問代詞(what, which, who, whom, whose)或疑問副詞(where, when, how, why)，以及連詞whether構(gòu)成特殊的不定式短語，其作用相當(dāng)于一個從句，這樣的不定式短語常在某些動詞后面作賓語。
常見的可以接這種不定式短語的動詞有：know, see, decide, tell, ask, consider, discover, explain, find out, forget, guess, hear, imagine, inquire, learn, observe, perceive, remember, think, understand, wonder等。
【例如】
I couldn't decide which book to choose. I can tell you where to get this book. They found it hard to decidewhether to go swimming next Sunday or to visit Aunt Sally in New Year.
"wh word+不定式"結(jié)構(gòu)除了作賓語外，還可以在句中作主語或者表語。
【例如】
When to start the program remains undecided.
The question is how to put the plansintospractice.
5)不定式作狀語
a)不定式作狀語表示目的?；蛴糜趕o as和in order之后，來強調(diào)這種目的。
【例如】
To learn a foreign language well, you must make painstaking efforts.
Mother saved every cent she could spare to pay for my schooling.
We must develop science and technology at high speed so as to raise scientific and cultural level of our country.
Insgroups to get a high mark in Band 4, he did a lot of exercises both in grammar and reading comprehension.
b)不定式表示結(jié)果，特別是在so……as to, such……as to, only to……以及too……to等結(jié)構(gòu)中的不定式表示結(jié)果。
【例如】
I rushed to the station as fast as I could, only to find the train already gone.
She left her hometown with her beloved man, never to return.
No one is too old to learn.
Would you be so kind as to carry the luggage for me?
c)不定式常用來修飾形容詞，構(gòu)成下列詞組：be able to, be afraid to, be apt to, be bound to, be certain to, be easy to, be eager to, be fit to, be likely to, be ready to, be sure to, be unable to, be unwilling to, be willing to等。
【例如】
Chinese team is bound to win the World Cup.
It is likely to rain today, for it is very cloudy.
I am willing to help you with your homework, for we are friends.
6)不定式作賓語補語不定式常跟在下列動詞之后作賓語補語：
ask, advise, allow, beg, cause, compel, command, enable, encourage, expect, feel, force, find, hear, have, inform, invite, let, make, mean, notice, order, permit, persuade, remind, require, request, teach, tell, urge, watch, warn, watch等。
【例如】
Because of the complexity of the modern equipments, most offices require secretaries to have specified training.
He asked you to call him at ten o'clock.
The note reminds me to be careful whatever I do.
I'd never allow my children to behave like that.
當(dāng)不定式在let, make, have, hear, look at, listen to, feel, observe, watch, notice, perceive(感覺到)等動詞后面作賓語補語時， 不定式不帶to.
【例如】
Whenever something is wrong with you, please do let me know.
I will have the students write a passage about Internet.
I saw my mother shed tears at the news that the neighbor girl got seriously hurt in a car accident.
It seemed so long before he heard the stone hit the water.
7)不定式作主補帶有賓語及賓語補足語結(jié)構(gòu)的動詞變?yōu)楸粍诱Z態(tài)時，原來的賓語變?yōu)橹髡Z，賓補則變?yōu)橹餮a。加主補的動詞主要有：assume, believe, know, report, say, suppose等。
【例如】
Mr. Brown is said to have left for Italy last week.
(It is said that Mr. Brown left for Italy last week.)
Persons have been said to climb on roofs, solve mathematical problems, compose music, walk through windows and commit murder in their sleep.
He is reported to have won the 100meter running race in the Olympic games.
常見的可以接這種不定式短語的動詞有：know, see, decide, tell, ask, consider, discover, explain, find out, forget, guess, hear, imagine, inquire, learn, observe, perceive, remember, think, understand, wonder等。
【例如】
I couldn't decide which book to choose. I can tell you where to get this book. They found it hard to decidewhether to go swimming next Sunday or to visit Aunt Sally in New Year.
"wh word+不定式"結(jié)構(gòu)除了作賓語外，還可以在句中作主語或者表語。
【例如】
When to start the program remains undecided.
The question is how to put the plansintospractice.
5)不定式作狀語
a)不定式作狀語表示目的?；蛴糜趕o as和in order之后，來強調(diào)這種目的。
【例如】
To learn a foreign language well, you must make painstaking efforts.
Mother saved every cent she could spare to pay for my schooling.
We must develop science and technology at high speed so as to raise scientific and cultural level of our country.
Insgroups to get a high mark in Band 4, he did a lot of exercises both in grammar and reading comprehension.
b)不定式表示結(jié)果，特別是在so……as to, such……as to, only to……以及too……to等結(jié)構(gòu)中的不定式表示結(jié)果。
【例如】
I rushed to the station as fast as I could, only to find the train already gone.
She left her hometown with her beloved man, never to return.
No one is too old to learn.
Would you be so kind as to carry the luggage for me?
c)不定式常用來修飾形容詞，構(gòu)成下列詞組：be able to, be afraid to, be apt to, be bound to, be certain to, be easy to, be eager to, be fit to, be likely to, be ready to, be sure to, be unable to, be unwilling to, be willing to等。
【例如】
Chinese team is bound to win the World Cup.
It is likely to rain today, for it is very cloudy.
I am willing to help you with your homework, for we are friends.
6)不定式作賓語補語不定式常跟在下列動詞之后作賓語補語：
ask, advise, allow, beg, cause, compel, command, enable, encourage, expect, feel, force, find, hear, have, inform, invite, let, make, mean, notice, order, permit, persuade, remind, require, request, teach, tell, urge, watch, warn, watch等。
【例如】
Because of the complexity of the modern equipments, most offices require secretaries to have specified training.
He asked you to call him at ten o'clock.
The note reminds me to be careful whatever I do.
I'd never allow my children to behave like that.
當(dāng)不定式在let, make, have, hear, look at, listen to, feel, observe, watch, notice, perceive(感覺到)等動詞后面作賓語補語時， 不定式不帶to.
【例如】
Whenever something is wrong with you, please do let me know.
I will have the students write a passage about Internet.
I saw my mother shed tears at the news that the neighbor girl got seriously hurt in a car accident.
It seemed so long before he heard the stone hit the water.
7)不定式作主補帶有賓語及賓語補足語結(jié)構(gòu)的動詞變?yōu)楸粍诱Z態(tài)時，原來的賓語變?yōu)橹髡Z，賓補則變?yōu)橹餮a。加主補的動詞主要有：assume, believe, know, report, say, suppose等。
【例如】
Mr. Brown is said to have left for Italy last week.
(It is said that Mr. Brown left for Italy last week.)
Persons have been said to climb on roofs, solve mathematical problems, compose music, walk through windows and commit murder in their sleep.
He is reported to have won the 100meter running race in the Olympic games.