Chapter 4 不定式
4.9 不定式的逻辑主语
4.9 不定式的逻辑主语
我们先要简单说明一下什么是逻辑主语，然后分别讨论不定式的逻辑主语的两种构成方式。
4.9.1 何谓逻辑主语
在英语中，逻辑主语都是针对非谓语动词来说的。对于三种非谓语动词都有一个逻辑主语的问题，这是因为它们都是动词的变化形式。既然是动词，就应该有动作的执行者，即主语。之所以称之为逻辑主语，是为了区别于句子结构上的语法主语，因为句子谓语的主语和非谓语动词的逻辑主语并不总是统一的，有时并不一致。请比较：
1 He was anxious to meet you.
2 He was anxious for his sister to meet you.
妙语点睛 在例句1中，句子的主语是he，不定式to meet的动作也是由he发出，因此he也是不定式的逻辑主语。此时我们说，句子的主语和不定式的逻辑主语一致。在例句2中，句子的主语是he，不定式to meet的动作不是由he发出，而是由his sister发出，因此his sister是不定式的逻辑主语。此时我们说，句子的主语he和不定式的逻辑主语his sister不一致。
对于动名词和分词，同样存在句子的主语和逻辑主语或一致、或不一致这两种情形，对此我们将在第五章和第六章分别讨论。在此先分析不定式的逻辑主语。
4.9.2 不定式逻辑主语的构成（一）：for+名词或代词+to do
从以上例句我们看出，不定式逻辑主语的构成通常是在to do前面添加for引导的一个介词短语，从而构成“for+名词或代词+to do”结构，这里的名词或代词即为不定式动作的逻辑主语。比如我们在4.7节中讨论过的这个句子：
1 Monkey-hunters use a box with an opening at the top, big enough for the monkey to slide its hand in, inside the box are nuts. The monkey grabs the nuts and now its hand becomes a fist. The monkey tries to get its hand out but the opening is big enough for the hand to slide in, but too small for the fist to come out. Now the monkey has a choice, either to let go of the nuts and be free forever or hangs on to the nuts and get caught. Guess what it picks every time? You guessed it. He hangs on to the nuts and gets caught.
妙语点睛 这里都是采用了for来引导不定式的逻辑主语。具体来说，不定式to slide its hand in的逻辑主语是the monkey，而该句的主语是monkey-hunters；不定式to slide in的逻辑主语是the hand，而该句的主语是the opening；不定式to come out的逻辑主语是the fist，而该句的主语是the opening。所以我们看到，这里的句子的主语与不定式的逻辑主语都是不一致的。
请再比较：
2 1） The father will be proud for his son to win the gold medal.
2） The father will be proud to win the gold medal.
妙语点睛 在例句1）中，不定式to win的逻辑主语是his son，而该句的主语是the father，即句子的主语与不定式的逻辑主语是不一致的。在例句2）中，the father既是句子的主语，同时也是不定式to win的逻辑主语，即句子的主语与不定式的逻辑主语是一致的。所以，我们看到两句话的差别在于：例句1）中夺金的是his son，例句2）中夺金的是the father。
3 He was very willing for everyone else to come.
在以上的例句中，不定式“for+名词或代词+to do”结构都是用在作表语的形容词后面的，此时的不定式短语相当于一个状语，比如表示结果（如the opening is big enough for the hand to slide in）、条件（如for his son to win the gold medal）或其他意义。下面我们来看看不定式短语“for+名词或代词+to do”作主语的例子：
4 It's important for you to go there in person.
妙语点睛 注意这里的不定式for you to go there in person虽然表面上也是在形容词important后面，但实际上是作主语的，所以原句的结构是For you to go there in person is important.
5 It is very common for him to be absent without leave.
妙语点睛 注意这里的不定式for him to be absent without leave虽然表面上也是在形容词common后面，但实际上是作主语的，所以原句的结构是For him to be absent without leave is common.
下面我们再来看不定式“for+名词或代词+to do”结构放在名词后面作定语的例子。比如：
6 Both Chinese and American parents were asked what they wanted most for their children. Chinese parents wanted their children to be successful, while American parents expressed a desire for their children to be happy.
妙语点睛 该句中的不定式短语for their children to be happy是在desire后面作定语，表示同位关系。
这就是中美文化的差异或者说是价值观念的差异——要幸福还是要成功？每个人都有自己的答案，但也许很难选择，因为幸福与成功之间并不能画等号。最好是做一个在物质与精神两方面都很富有的人。
我们下面来看不定式“for+名词或代词+to do”结构作目的状语的例子：
7 For any adhesive to make a really strong bond, the surfaces to be glued must be absolutely clean and free from moisture or grease.
妙语点睛 该句中的不定式短语for any adhesive to make...放在句首作目的状语。
再比如下面这个例句：
8 Hilary: Hi Catherine. How's life?
Catherine: Everything's great! How are you and Kevin?
Hilary: We’re fine, too. You should find a boyfriend and then we all could go out on dates together.
Catherine: Not for me! I think campus love is a waste of time. I’d rather be studying.
Hilary: But studying all the time is so boring! You need to enjoy life while you’re here. I know I do.
Catherine: You know my parents have sacrificed a lot for me to come here. They want me to do well. How will they feel if they hear that I’m spending most of my time with my boyfriend instead of my textbooks!
妙语点睛 该句中的不定式短语for me to come here用在句末作目的状语。
我们下面来看不定式“for+名词或代词+to do”结构作表语的例子：
9 The eye of an animal is quite easy to see. How then can the eyes be prevented from spoiling the animal's blending with its environment? One solution would be for the animal to keep its eyes closed when danger threatens.
妙语点睛 该句中的不定式短语for the animal to keep...放在be动词后面作表语。
综上所述，不定式的逻辑主语常由“for+名词或代词”引出，这里的“名词或代词”即是不定式的逻辑主语，来说明不定式动作的执行者。这个“for+名词或代词+to do”结构在句中可以作状语、主语、定语或表语等等。
4.9.3 不定式逻辑主语的构成（二）：of sb. to do
除了上面讨论的for引导不定式的逻辑主语外，在某些特殊情况下，我们要用of来引导逻辑主语。这种特殊情况就是我们在4.6.3小节讨论过的这样的形容词：用来说明人的性格特征或行为表现的形容词，当它们与不定式连用时，要用“of+名词或代词”这一结构引出不定式的逻辑主语。这样的形容词主要有：brave, careful, careless, clever, cruel, foolish, generous, kind, modest, nice, polite, rude, selfish, silly, stupid, thoughtful等。请看例句：
1 It's wise of you not to argue with your boss.
2 It's generous of him to lend me his car.
3 It was very careless of him to make such silly mistakes.
这种结构的用法非常有限，仅限于作主语的不定式，不能像“for+名词或代词+to do”结构可以用来作各种成分，比如作状语、主语、定语或表语等等。
另外值得注意的是，用of的句子，可以用“人”作主语将句子改写，而用for的句子则不能。试比较：
4 1） You are wise not to argue with your boss.
2） You are important to go there in person. *
究其原因，是因为wise是强调人的性格特征或行为表现的，所以可以用“人”作主语；而important这样的形容词是强调事情的，不是强调人的，所以不能用“人”直接作它的主语。关于这一点，读者可参见4.6.1小节的内容。
思维总结
不定式的逻辑主语主要是通过介词for来引导，此时不定式的逻辑主语与句子的主语是不一致的。另外，对于某些形容词则要用of来引导不定式的逻辑主语，读者对这些形容词要特别注意。
思维训练4.9 Key
选择最佳答案填空。
1. It is wise ______ the experiment that way.
A. of him to do B. for him to do C.of his doing D.that he do
2. ______ a really strong bond, the surfaces to be glued must be absolutely clean and free from moisture or grease.
A. Any adhesive to make B. To make any adhesive
C. For any adhesive to make D.Making any adhesive
3. Both Chinese and American parents were asked what they wanted most for their children. Chinese parents wanted their children to be successful, while American parents expressed a desire ______ happy.
A. their children to be B. for their children C.their children are D.for their children to be