A. to lose B. losing C. to be lost D. being lost
选B。本题考非谓语动词作宾语。在动词risk之后，习惯用-ing分词作宾语，所以A、C两项不考虑。而空格后面有the good opportunity是lose的宾语，所以此-ing分词不可能是被动，所以选B。
05年（春）33题
Accustomed to ____ the steep mountains, he had no difficulty reaching the top. A. climbing B. climb C. having climbed D. have climed
选A。词组accustomed to的to是介词，所以后面必须跟动名词。accustomed to的意思是?习惯于......?。
06年31题
. Eugene’s never willing to alter any of his opinions. It’s no use ____ with him. A. to argue B. arguing C. argued D. having argued 选B。在句型It’s no use后习惯用doing，而非其他。
06年（春）29题
The parents suggested ____ in the hotel room but their kids were anxious to camp out during the trip.
A. sleep B. to sleep C. sleeping D. having slept 选C。suggest后只能跟动名词作宾语。
07年（春）33题
All the staff in our company are considering ____ to the city centre for the fashion show. A. to go B. going C. to have gone D. having gone
选B。在动词consider之后，应该用动名词作宾语，不能用不定式，而且?考虑去做某事?一定是还没有做，所以不可能选having gone。
语法讲座：不定式 一、不定式的形式
1．不定式的时态与语态
不定式的时态与语态一共有六种形式，现以动词do为例，列表如下：
to do to have done to be doing to have been doing to be done to have been done A)不定式的一般式to do
to do所表示的动作一般发生在谓语动词之后，但也可以是在谓语动词之前或与谓语动词几乎同时发生。
eg. I have a lot of work to do. To improve your English, you should practise reading aloud every day. He seems to know the answer. I’m glad to see you. B)不定式的完成式to have done
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to have done所表示的动作都发生在谓语动词之前。 eg. I am sorry to have brought you so much trouble. She seems to have read the book. C)不定式的进行式to be doing
to be doing所表示的动作与谓语动词同时发生。 eg. It happened to be raining when I arrived. The child pretended to be sleeping when his mother came in. D)不定式的完成进行式to have been doing
to have been doing所表示的动作，是从谓语动词之前某一个时间开始，进行到谓语动词所表示的时间。
eg. He is said to have been writing a play for months. The man seemed to have been lying on the ground for a while. E)不定式的一般被动式to be done
to be done所表示的动作是被动的意义，多为发生在谓语动词之后，但有时也可以是在谓语动词之前或几乎与谓语动词同时发生。
eg. The new underground railway is said to be opened to traffic at the end of this year. It’s an honour for me to be asked to speak here. 注：有的时候，不定式所表示的动作虽然有被动意义，但我们不用被动形式，仍然用主动形式。这种现象主要在以下几种情况下出现：
a)在一些形容词如easy, difficult, hard, nice, interesting, important, pleasant, dangerous, heavy, light, fit之后。
eg. My bag is very heavy to carry. The sentence is easy to understand. The water is not fit to drink. I found the text difficult to translate into Chinese. 这类的句子都可以用以it开头的句子来改写。如：It is heavy to carry my bag. I found it difficult to translate the text into Chinese. b)这个不定式与最近的一个名词或代词的关系是被动，但是在前面我们可以找到这个动作的执行者。
eg. I have a lot of work to do. Will you please give me some books to read? 试分析：I have five letters to type today. I have five letters to be typed today. c)在there be句型中的不定式，如果是被动的意义，我们可以用被动式，也可以用主动式。
eg. There is nothing to do. There is nothing to be done. F)不定式的完成被动式to have been done
to have been done所表示的动作是被动意义，发生在谓语动词之前。 eg. He was proud to have been chosen captain of the team. The book is said to have been translated into English. 2．不定式的否定形式
不定式的否定形式就是把not加在to之前。 eg. Take care not to catch cold.
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The student pretended not to be listening. They are said not to have finished the work now. 3．不定式的逻辑主语
不定式的逻辑主语可以用for sb放在不定式之前。 eg. It’s not necessary for you to do so many exercises. It’s important for us to master a foreign language. 二、不定式的功能 1．作主语
不定式作主语时一般都看成单数。 eg. To be an astronaut is his dream. To make mistakes is human. 不定式作主语可以用it作形式主语，而把真实主语放在后面。 eg. It is nice to hear your voice. It is impossible to live without air. 在作主语的不定式的前面还可以加上疑问词，如what to do, when to do, where to do,以及whether to do等。（注意：没有if to do的说法！） eg. What to do next has not been decided yet. Whether to carry out the project will be discussed later. 注：不定式作主语与动名词作主语的区别我们已经在学习动名词时讨论过了，此处不再重复。
2．作表语
eg. His ambition is to open a shop of his own. His theory proved to be true. What surprised me most was to see my father in the principal’s office. ―wh- + to do‖的形式也能作表语。
eg. Our problem was how to get those involved informed as soon as possible. 注：不定式作表语与动名词作表语的区别我们已经在学习动名词时讨论过了，此处也不再重复。 3．作宾语
eg. He refused to give me a hand. Tom failed to pass the English exam. Little Alice appeared to have caught cold. ―wh- +to do‖的形式也能作宾语。
eg. We have decided where and when to hold a meeting. The old man taught me how to catch fish with the net. 如果在不定式宾语的后面还有宾语补足语的话，可以用it作形式宾语，而把真实宾语放到后面。
eg. I found it not easy to persuade him to change his mind. 4．作宾语补足语
eg. The teacher advised me to read a lot. His illness caused him to miss the game. 注：在一些感觉动词与使役动词后面的不定式宾语补足语要省略?to?，这些动词是see, look at, notice, watch, observe, hear, listen to, feel; make, have, let等。help后的宾补的to可以省略，也可以保留。
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eg. I noticed a man steal into the office. They heard the space ship take off with a very loud noise. Don’t let the children play in the street. I will have them check it again. I’ll help you (to) carry the bag upstairs. 但如果这个动词是被动语态，那么?to?就不省略。 eg. The poor boy was made to copy the text ten times. He was seen to quarrel with an old man. 注：不定式与分词都能用作宾语补足语，如果是主动的则现在分词与不定式都可以用，但分词强调动作在进行当中，而不定式则可能动作已经完成，强调整个过程，或是带有将来的意义。如果宾语与宾补的关系是被动的，那么就选用过去分词，偶尔也可看到用being done。
试比较：I heard the telephone ringing in the office.
I heard the telephone ring three or four times in the office this morning. I once heard the song sung in English. I heard the boy being scolded by his mother.
He had the boy standing at the corner. He had the boy do the exercise again. He had the watch mended again. 5．作定语
不定式作定语，放在被修饰词之后。
eg. He worked out a plan to help his brother. Have you anything to say about it? Tom was the first to come this morning. 注：不定式作定语，经常用在something, anything, nothing与序数词之后。并要特别注意不定式定语时，有时与被修饰词之间所用的介词不能忘记。 eg. The first thing for him to do is to find a room to live in. You won’t have anything to worry about. Please find me a knife to cut the paper with. 与分词相比较，不定式作定语常带有将来的意义。 试比较：Do you know the name of the book by Mr Glen? to be translated being translated translated
6．作状语
不定式经常用作目的、原因和结果状语。
eg. She worked day and night to pay for the debt To be a teacher, one must first be a pupil. I am glad to meet you. He was sad to hear the news. I hurried to the station only to find the train gone. The boy woke up to find his bag of money missing. 与分词作状语一样，不定式作状语时，也要注意它的逻辑主语应该与句子的主语一致。
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