不定式短语作定语时什么时候用主动什么时候用被动形式?
1、不定式修饰的名词或代词和不定式逻辑上构成主谓关系时，不定式往往用主动式。eg:
Have you got a key to unlock the door?
2、不定式和它前面被修饰的名词或代词构成逻辑上的动宾关系，又和该句主语构成逻辑上的主谓关系时，不定式常用主动形式。 eg:
I have got a letter to write.
He need a room to live in.
3、 在there be 句型中，当说话人考虑的是必须有人去完成某件事时，不定式用主动形式；如果说话人强调的事情本身必须完成，则用被动形式。 eg:
There is a lot of work to do. (Somebody has to do the work.)
There is a lot of work to be done. (The work has to be done.)
高中知识：
不定式作定语，用主动式还是被动式？
不定式是非谓语动词的重要情形之一。由于它具有名词、动词、形容词和副词的多种特征，所以在句中可以作主语、宾语、表语、状语、宾语补足语、主语补足语、同位语或独立成分。
不定式作定语时兼有主动式和被动式两种形式，用主动式还是被动式？这往往是不少同学感到棘手的问题。现归纳如下，供同学们学习时参考。
一、不定式作定语只能用主动式的情形：
1．不定式所修饰的名词和不定式中的动词所表示的动作是逻辑上的主谓关系（此时，该不定式短语可转化为一个定语从句）。例如：
实拍高考阅卷现场
Li Xuemei was the first athlete to get to the finishing line.（＝．．．athlete who got to the finishing line）．李雪梅是第一个到达终点的选手。
We need someone to help to repair the computer.（＝．．．someone who will help to repair the computer）．我们需要一个能帮助我们修电脑的人。
He is always the first to bear hardships.（＝．．．the first who will bear hardships），the last to enjoy comforts（＝the last who will enjoy comforts）．
他总是一个吃苦在前，享乐在后的人。
2．不定式与它修饰的名词是逻辑上的动宾关系，且主语是不定式中的动词所表示动作的逻辑主语或在句中能找到其逻辑主语。例如：
He has a lot of work to do today．今天他有大量的活要干。
Do you have anything more to say？你还有什么话要说吗？
Our teacher arranged us six exercis to do at home．老师给我们安排了六道练习题在家里做。（us是to do的逻辑主语）
Father always bought his son some toys to play with after his business．父亲每次出差回
来都给他的儿子买玩具玩儿。（son是to play with的逻辑主语）
3．有些句子中，尽管行文上没有不定式的逻辑主语，但是从句意角度可以体会出不定式中隐含着“for sb．to do”结构。此时，不定式应该用主动式。例如：
There is nothing（for us） to worry about．没有什么可值得担忧的。
That will be the only thing（for us）to do now．这恐怕是目前（我们）唯一可行的办法。
It is a good opportunity（for us ／them）to learn from the farmers．这可是一个向农民学习的大好机会。
4．部分形容词，如eager，anxious，determined，able等，其后常跟不定式，他们的同源名词后要用不定式的主动式作定语。例如：
（Mr．Smith was eager to get back to teach at the school．）
Mr．Smith's eagerness to get back to teach at the school was quite obvious．史密斯先生急于回校教学这一点是显而易见的。
三年零班（He was anxious to know the results of the test．）
种植石斛
We could e his anxiety to know the results of the test．我们看得出他很想知道这次测验的结果。
（They were determined to catch up withus．）
In their speech they expresd their determination to catch up with us．他们在讲话中表达了他们要赶上我们的决心。
朝花夕拾手抄报内容5．部分动词，如attempt，promi，plan， intend，refu等，其后常跟不定式作其宾语，它们的同源名词后要用不定式的主动式作定语。例如：
（They attempted to reach there before five o'clock．）
They failed in their attempt to reach there before five o'clock．他们试图在五点以前赶到那里，但是没有办到。
（You promid to give me a prent on my birthday．）
You haven't kept your promi to give me a prent on my birthday．你没有遵守在我过生日时给我礼物的诺言。
（They are planning to be in business on National Day．）
I guess they will make some changes in their plan to be in business on National Day．我猜他们在国庆节开始营业的计划得做些变动了。
6．在“with ／without ＋宾语＋宾语补足语”结构中，若宾语补足语是不定式（作定语），不定式所表示的动作将要发生，且句子的主语是该动作逻辑上的执行者，此时不定式须用主动式。例如：
With a lot of difficult problems ___________ ， the newly-elected president is having a hard time．（2002上海高考）
A．ttled B．ttling C．to ttle 堆词组D．being ttled
With veral meetings to attend，he couldn't go to the Great Wall with us．由于有几次会议要参加，所以他不能和我们一起去长城了。
Without two members to come，we'd better not start the meeting．还有两位成员未到，我们最好先别开始开会。
六级写作Without anything to do，he turned off the lights and went to bed．已无事可做，所以他关灯睡觉了。
二、不定式作定语只能用被动式的情形：
1．为了表达需要，强调不定式动作的执行者时，须用被动式，常用by结构引导。例如：
2008 Olympic Games is the first great Olympic Games to be held by Chine．2008年奥运会是中国人首次举办的奥运盛会。
2．不定式所修饰的名词是将要被做的事情时，不定式须用被动式。例如：
The problem to be discusd at the next meeting is of great importance．下次会议上将要讨论的这个问题至关重要。
The building to be built next year will be ud as the office building．明年要建设的大楼将
用作办公楼。
He invented a new game to be played during the long cold winters. 他发明了一种新的在漫长而又寒冷的冬季里可以被用来玩的运动。
注意：在“There be”结构中，主语被不定式修饰（不定式作定语）时，既可用主动式，也可用被动式，意义上无甚区别。例如：
There was a lot of problems to deal with／to be dealt with．有许多问题需要处理。
巩固练习：用括号内所给动词的适当形式填空。 对逝者的悼念短句
1．He is not a man __________（bow）before difficulties．
2．They had no chance for them __________（go）abroad in tho years．
3．You should have confidence in your ability __________（finish）the task ahead of time．
4．Does he have the intention __________（attend）Mary's wedding party with us？
5．This will be one of the greatest bridges __________（build）by our company this year．
鲟鱼怎么做最好吃6．There is no farmland __________（lo）．
