非谓语动词什么时候用不定式，过去分词或者ing形式？

非谓语动词解题策略

1） 正确判断非谓语动词

这类题一般出现在独立主格结构中，如果在选项与句子之间没有连词，则说明，所选为独立主格结构，既名词或主格代词 + 分词。
All things ______, the planned trip will have to be called off.
A. considered B. be considered
C. considering D. having considered (1998.6)
句子没有连词，说明所选结构不属于从句，那么就是独立主格做状语，根据动词与其逻辑主语之间的关系为动宾关系，答案应该是A。
____, a man who expresses himself effectively is sure to succeed
more rapidly than a man whose command of language is poor.(1997.6)
A. Other things being equal B. Were other things equal
C. To be equal to other things D. Other things to be equal
做状语的可以是从句，但B的结构是虚拟条件，与这里不符，不表目的，C不对，不表将来，独立主格中非谓语动词不能是不定式，答案为A。

4） 判断动名词复合结构的方式

主语位置上，或动词、介词后的"名词代词 + 非谓语动词"，如果表示的是一个事件则是动名词复合结构，而不是"名词 + 定语。请看以下各例：
He insisted on the windows _____ open while he was sleeping.
A. left B. being left C. leaving D. be left
insist on后不接从句，D可以排除。这里表达的是坚持要求"开着窗子睡觉"，所以应该是动名词复合结构，答案为B。
The road __________ caused us to be for our work for half an hour.
A. blocked B. was blocked C. blocking D. being blocked
做主语的表示上班迟到的原因，自然应该是"交通堵塞"，而不是"被堵的道路"，所以还是动名词复合结构，答案为D。
The concerned mother thrilled at the news of his son _________ to college.
A. had been admitted B. admitted
C. having been admitted D. having admitted
消息表达的应该是个事件，说明不是"被录取的孩子"，介词of后不可能接从句，说明of后为动名词的复合结构，答案是C。

3） 注意分析非谓语动词与其逻辑主语之间的关系

正确判断非谓语动词与起逻辑主语之间的关系是正确选择非谓语动词形式的保证，不管是做什么成分的非谓语动词都体现以下特点：
如果非谓语动词与逻辑主语之间是主谓关系，则用现在分词；
如果非谓语动词与逻辑主语之间是动宾关系，则用过去分词；
如果表示将来，则用动词不定式。
这是非谓语动词运用的基本原则，然后再根据其不同的作用，掌握其更细的规则。如：
(1)做定语时
做定语的可以是动名词、分词或不定式。动名词做前置定语，所构成的大多为固定短语，四级考试一般不涉及。主要考查分词和不定式做定语。分词或不定式做定语一般做后置定语。
① The project ____ by the end of 2000, will expand the city's
telephone network to cover 1,000,000 users.
A. accomplished B. being accomplished
C. to be accomplished D. having been accomplished
② Hard work ____ on time will lead to better grades.(1995.1)
A. done B. be done C. having done D. to have been done
③ As early as 1647 Ohio made a decision that free, tax-supported
schools must be established in every town _____ 50 households
or more.(1998.1)
A. having B. to have C. to have had D. having had
④ Those _____ to the conference were mostly famous scientists.
A. invited B. were invited C. inviting D. to invite
做定语的非谓语动词有一下几种形式：
"doing 结构":分词与中心词之间是主谓关系,表示正在进行,或状态。如③
"being done结构"：分词与中心词之间是动宾关系，表示被动和正在进行，如：No one is to enter the buildingbeing repaired.
"to be done结构"：不定式与中心词之间是动宾关系，表示将来和被动，如①。
"done结构"：分词与中心词之间是动宾关系，表示被动、完成或一般，如②④。
"to do结构"：不定式与中心词之间是主谓关系，表示将来。如：The professor to give us a speechtomorrow is said to have compiled many scientific works.
完成形式不能做定语，包括分词的完成形式和不定式的完成形式。
(2)做状语
做状语的可以是不定式，也可以是分词。大体结构有：
"doing 结构"：分词与句子主语为主谓关系，表示与谓语动词同时发生，或基本上同时发生，或是同时存在的状态。如：
______ the earth to be flat, many feared that Columbus would fall off the edgeof the earth.
A. Having believed B. Believing
C. Believed D. Being believed
"done结构"：只要分词与句子主语间是动宾关系就可以用过去分词，可以表示完成，可以表示正在进行，也可以表示条件。如：
_______ in this way, the situation doesn't seem so disappointing.
A. Too look at B. Looking at
C. Looked at D. To be looked at (2000.1)
He came in, followed by a group of reporters.
"having done结构"：分词与句子主语是主谓关系，切发生在谓语动词之前。Having seen the film already,I declined his invitation to go to the cinema.
"having been done结构"：该结构表示完成被动，即分词与句子主语之间是动宾关系，切发生在谓语动词之前。如：Havingbeen showed many times, he still didn't understand the operation of the machine.
"to do 结构"：这是不定式结构，在句中可以做目的状语，也可以做结果状语，但不定式动作总是发生在谓语动词之后。如：
_______ a teacher in a university, it is necessary to have at
least a master's degree.
A. To become B. Become C. One becomes D. On becoming
表结果时一般为固定结构，如too …to…, enough to….，或是表示出乎意料的结果，常可加构成only to的结构。如：
I did what I could to comfort her only to make her cry even more.
The next day, she woke to find herself in hospital.
"being done结构"：该结构表示被动与正在进行，一般置于句首，表示原因。如：Being chased by some spies,he hid himself in the grass.
(2)做表语
测试中对表语的考查主要侧重在现在分词与过去分词的区别上，所以对于做表语的非谓语动词，主要看分词与句子主语之间的关系。做表语的分词一般只有doing和done两种形式。现在分词表示做表语的与主语是主谓关系；过去分词表示做表语的与主语之间是动宾关系。根据使用规律，如果主语是无生命名词，则表语分词为现在分词；如果主语是有生命名词，以过去分词居多，但也可以用现在分词，但意思不同。如：
How disappointed he felt at the result of the election. (他感到失望)
How disappointing he is. He should have failed in such an election. (他令人失望）
可接表语的系动词很多，除be外还有remain, feel, look, appear, seem, get, become, go。
(3)做补足语
一般做宾补的非谓语动词动词的形式选择与其它成分中的非谓语动词形式选择规则基本相同。
doing结构：分词与宾语构成主谓关系，表正在进行。
When I caught him ____ me I stopped buying things there and
started dealing with another shop.
A. cheating B. cheat C. to cheat D. to be cheating
done结构：分词与宾语构成动宾关系，表示被动与完成。
Don't get your schedule _____;stay with us in this class.(1996.1)
A. to change B. changing C. changed D. change
to do 结构：不定式表示将来，如wish somebody to do, expect somebody to do, arrange for somebodyto do等等。
being done结构：表示被动和正在进行, watch the flag being raised
Corn originated in the New World and thus was not known in Europe
until Columbus found it _____ in Cuba.(2000.1)
A. being cultivated B. been cultivated
C. having cultivated D. cultivating
to be done结构：用语表示将来与被动，一般用语主谓关系时可用to做宾补的动词后，如：want something to be done, ordersomething to be done
完成形式不能做宾补。

4） 注意分析非谓语动词做什么状语

不同的状语对非谓语动词的要求不同，如表示目的只能是不定式，另外，测试中也常有选择非谓语动词前连词的试题。因此，同学们应注意根据状语与句子间的关系，判断连词的使用。5） 注意不定式的特殊句式

不定式在做定语和做状语时都有其特殊句式，注意这些句式的特点，考试中就会少走一点弯路。如：
have something to do类：
这类结构相当于汉语的连动结构，即"有事要做"，"买东西吃"，"借书看"等。
a room in which to live类：
该类结构是a room to live in 的变体。但如果不熟悉这个结构，考试中则难以决断。如：
You will want two trees about ten feet apart, from _____ to
suspend your tent.(1998.1)
A. there B. them C. which D. where
The professor could hardly find sufficient grounds _____ his
arguments in favor of the new theory.(2000.6)
A. to be based on B. to base on
C. which to base on D. on which to base
the first to do
该结构表示如果名词前有序数词、形容词最高级或序数词、最高级本身做名词用，其后应不定式做定语。
the ability to do
该结构表示，形容词变了的名词后用不定式做定语。
the need to do
该结构表示由动词变来的名词后用不定式做定语。
the way to do
该结构表示，在一些特定的名词后面常用不定式做定语，应注意记忆，如means, reason, time, pressure, moment。

6） 熟记固定搭配，分清不定式与to加动名词

其实容易产生不定式符号与介词混淆的只是为数不多的某些句式，只要平时注意积累即可。
prefer doing something to doing something
look forward to doing something
be used to doing something (习惯于做某事)
stick to doing something
object to doing something/ have objection to doing something
be opposed to doing something
admit/confess to doing something

I have no objection _____ your story again.(2000.6)
A. to hear B. to hearing C. to having heard D. to have heard
The man in the corner confessed to ________ a lie to the manager of the company.
A. have told B. be told C. being told D. having told
从出题人的心理来看，如果有to do something和 to doing something的对比项，一般答案是to doing something。

7） 分清宾补的类别

(1)感官动词后的宾补可以是
doing, do, done, being done的结构，其中being done 只用于少数动词后面， 如find, smell, feel等。
(2)have somebody do something 让某人做某事
have somebody doing something 让某人一直做某事
won't have somebody do something 不许某人做某事
have something done 使某事被做
have something + ving 让……一直……
(3)catch,smell,keep,set,等只能接doing的结构,表示主动和正在进行。
(4)leave somebody doing something 让某人一直做某事
leave something undone 使某事只做了一半
leave something to be done 事情有待于解决
leave somebody to do something让某事做某事，表示将来
(5)with somebody to do something宾补与宾语是主谓关系，表示将来。
with somebody doing something 宾补与宾语之间是主谓关系，表示正在进行。
with something to do 宾补与宾语间是动宾关系，表示将来，动作执行者在句中找的着。
with something to be done宾补与宾语是动宾关系，表示将来，但动作执行者在句中找不着。
with something done 宾补与宾语之间是动宾关系，表示完成。 8） 注意下列结构中非谓语动词的体

pretend/appear/seem/happen/ be said to do something
不定式动作一般为状态动词，也可是终止性动词，表示与谓语动词同时存在或发生。
pretend/appear/seem/happen/ be said to have done something
不定式动作发生在谓语动词之前。
pretend/appear/seem/happen/ be said to be doing something
不定式动作与谓语动词同时进行

9)熟记哪些动词后接不定式,哪些接动名词,如果两者都可，又有什么差别。

既可接不定式,又可接动名词,用法有别的动词常考的有: forget,remember, regret, mean, try等。

10）注意want/need/require表示"需要"时的特殊句式

want/need/require表"需要"时，后接主动的动名词或被动的不定式，即doing 或to be done的形式。不可混淆。

第一句hope后面只能用接不定式或从句。
第二句be后面接V-ing时表示进行。be动词后面也可以用动词不定式或过去分词，但是be to do表示将来，be done为被动语态。另外，上面句子有误，应为I'm thinking of getting a book，因为of是介词，后面只能用名词、代词或V-ing形式。
第三句使用have sth done结构，have是使役动词，后面用过去分词时表示被动关系，即his wallet was stolen.

非谓语的TO DO 形式一般具有将来的意义，be doing 形式强调正在进行，过去分词一般都有被动的意义，你给的三句例句，第一句主要还是根据hope to do sth,的固定句型来看，第二句表示正在考虑，第三句是have sth done 的句型表示某人使某物被怎么样，和have my hair cut的意义是一样的。
非谓语动词的to do形式通常是与固定的句型相联系的，比如have sb do sth，get sb to do sth，hope to do sth，wish to do sth·····动词ing形式一般与动词前的词有关如介词+ving，be+ving···如果动词是放在句首做独立结构主要是看动作是主动看是被动承受来确定是用动名词还是过去分词。