动词不定式当主语的介绍,请举几个例子,谢谢
* 不定式表示目的或将要进行的事情;动名词表示状态或正在进行的事情.
* 作主语
1） It's easy (for me) to do that.我做这事太容易了
easy, difficult, hard, important, possible, impossible, comfortable, necessary, better;
the first, the next, the last, the best, too much, too little, not enough
It's so nice to hear your voice.
听到你的声音真高兴。
It's necessary for you to lock the car when you do not use it.
当你不用车的时候，锁车是有必要的。
2) It's very kind of you to help us. 他帮助我们，他真好。
Kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate(考虑周到的), silly, selfish(自私的)
例句:
It was silly of us to believe him. 我们真愚蠢，竟然相信了他。
It seemed selfish of him not to give them anything. 他不给他们任何东西，这显得太自私了。
注意：1) 其他系动词如，look，appear等也可用于此句型
2) 不定式作为句子成分时，动词用单数形式。
3) 当不定式作主语的句子中又有一个不定式作表语时，不能用It is… to…的句型
(对)To see is to believe. 百闻不如一见。
(错)It is to believe to see.
写几个动词不定式作主语的句子，不要抄书上的。
1、不定式的逻辑主语是泛指的，不明确的人或人们。
a) To see is to believe.
b) To plan is to act.
c) It always pays to tell the true.
2. 有时，通过句中的某个名词或代词，我们可以知道不定式的逻辑主语。
a) To clean the window is your duty.( 不定式的逻辑主语是 “you”)
b) To point out the difficulties is my purpose. ( 不定式的逻辑主语是 “I”)
这些情况都可以放句首。
动词不定式做主语补足语的句式结构及例句
sth/sb be said / reported / thought / believed / known / supposed + to do sth.
在不定式做宾补的结构中，把它变成被动语态中，宾补就做成主补
I wish you to study English well.(宾补)
You are wished to study English.(主补)
The doctor warned you not to eat too much meat. (宾补)
You were warned not to eat too much meat.(主补)
2.make /hear/see/observe /watch sb do sth 感官动词和使役动词 用省略to的不定式作宾补，变成被动语态是 不定式变成主补，to恢复
I heard someone come up the stairs.(宾补)
Someone was heard to come up stairs..(主补)
He always makes me cry..(宾补)
I am always made to cry..(主补)
不定式做主语
1、To love and to be loved is the greatest happiness in the world.
爱人和被人爱是这个世界上最大的幸福。
2、 这里可以用loving和being loved 来代替主语。比如：眼见为实就有两种翻译：Seeing is believing. 和 To see is to believe.
3、什么时候用不定式：
动词不定式在句子中可做任何成分，但不能做谓语。
(1）动词不定式做主语
eg: To swim with you was very enjoyable.
注：动名词和动词不定式均可以做主语和表语，但动名词表示经常性的，抽象的动作，而不定式表示特指的一次性的具体的动作
(2）动词不定式做表语
eg: Her wish is to become a teacher.
注：表语为不定式时，主语也是不定式；当主语部分含有动词do时，做表语的不定式可以省略to.
eg: To see is to believe.
All you have to do is (to) study hard.
(3)不定式做宾语
以下及物动词后常用动词不定式：
want,decide,aim(目标),manage(试图),hope,ask,happen,like,love,choose,prevent(阻止),promise,continue,plan,learn,fail等。
eg: I decide to look for a job.
(4)动词不定式做定语
动词不定式做定语往往要后置，与被修饰词之间存在动宾关系、主谓关系、同位关系和修饰关系。如果动词不定式是不及物动词，应该在动词后加上适当的介词。如果被修饰词是地点、时间、方法，通常省略动词不定式后的介词。
eg: I have something to say.(动宾关系）
I was the last one to leave here.(主谓关系）
I have no wish to quarrel with you.(同位关系）
This is the best way to do that.(修饰关系）
I have nothing to worry about.(不及物动词后加介词）
I can't find a place to play (in).(省略介词in)
注：当名词用特定的定语如：frist,last,next,only等以及形容词最高级修饰时，后面用不定式修饰。
eg: He is the only person to know the truth.
(5）不定式做状语
不定式做状语主要表达结果、目的和原因。
eg: He worked day and night to play for the debts.(目的状语）
He woke up to find everyone gone.(结果状语）
We laughed to hear the news.(原因状语）
注：动词不定式与only连用时，可表出乎意料的结果。
eg: He went to seaside only to be drowned.
(6)动词不定式做补语
eg: Allow me to introduce her to you.