A. too ... to do ...太……而不能
例：They are too young to understand what is going on
他们还太小，不明白发生了什么事。
《柯林斯高阶英汉双解学习词典》
I just decided I was a bit too frivolous to be a doctor
我刚刚决定说自己有点过于轻率，不适合做医生。
《柯林斯高阶英汉双解学习词典》
I was too cowardly to complain.
我太胆小，不敢抱怨。
《柯林斯高阶英汉双解学习词典》
It'll be too late to start preparing dinner when the guests have arrived.
客人到了才准备饭菜，就来不及了。
《汉英大词典》
We found the English treacle pudding too good to resist. Sure enough, it wasdelicious
我们觉得英国糖蜜布丁太好吃了，令人无法抗拒。的确非常美味。
《柯林斯高阶英汉双解学习词典》
Politics is too important to be left to the politicians.(=Politics is so important that it can't be left to the politicians.)
政治太重要了，不能由政治家来决定。
She was too excited to go to sleep. 她兴奋得睡不着了。
The ice is too thin to bear your weight. 冰太薄，承受不住你的重量。
She works too slowly to be much use to me. 她干活太慢，对我不会有多大帮助。
too…to…结构是英语中一个十分重要的结构，同时也是各种英语考试中一个十分重要的考点，同学们在学习或复习中应注意以下几点：
一、基本结构特点
too…to…结构的基本形式为“too 形容词或副词 to 动词原形”，其意为“太……以至于不能……”。如：
He is too shy to speak to her. 他太害羞，不敢同她讲话。
It's too cheap to be good. 这东西太便宜，好不了(即便宜无好货)。
He is too young to know right from wrong. 他太小，还分不清是非。
二、不定式的逻辑主语
有时不定式前可以带有一个由介词for引出的逻辑主语。如：
It's too expensive for her to buy. 太贵了，她买不起。
The box is too heavy for the boy to carry. 这个箱子太重，这男孩提不起。
The print is too small for me to read without glasses. 印刷字体太小，我不戴眼镜就看不清。
三、不定式是否带宾语
在通常情况下，too…to…结构中的不定式可根据其是否及物来确定它是否带宾语。如：
He is too tired to go any further. 他太累了，不能再往前走了。(不定式to go不及物，无需带宾语)
I was too weak to move or think or speak
我太虚弱了，无法动弹，无法思考，也无法说话。
《柯林斯高阶英汉双解学习词典》
I was too scared to move
我吓得动弹不得。
《柯林斯高阶英汉双解学习词典》
She is too poor to buy such a nice a dress. 她太穷，买不起那件漂亮的连衣裙。(不定式to buy后带有宾语 such a nice a dress)
但是，若句子主语与其后不定式有动宾关系，那么，其后的及物动词不定式不能带宾语。如：
The nice dress is too expensive for her to buy. 这件漂亮的连衣裙太贵了，她买不起。(to buy在此虽为及物动词，但由于句子主语the nice dress与该不定式to buy有动宾关系，故to buy后不宜再接代词it作宾语)
注意：若句子主语与其后不定式有动宾关系，且其中的动词为不及物动词，此时应注意在其后加适当的介词。如：
The room is too dirty to live in. 这房间太脏，不能住。(句末的介词in不可省略)
It's too late to back down now
现在打退堂鼓已经太晚了。
《柯林斯高阶英汉双解学习词典》
四、不定式是否用被动语态
上面讲到，若句子主语与其后不定式有动宾关系，其后作为及物动词的不定式不再带宾语。此时还需注意，该不定式通常也不用被动式，尽管意义上是被动的。如：
The text is too difficult to understand. 这课文太难了，理解不了。
The text is too difficult for the students to understand. 这课文太难了，学生理解不了。
但在某些特殊的语境，其中的不定式必须要用被动式。如：
He spoke in a voice too low to be heard. 他说话的声音太低，听不见。
He is too young to be sent to America for advanced study. 他太年轻，不能送到美国去深造。
This parcel is too heavy to send / to be sent by post. 这个包裹太重了，不能邮寄。
注意，有些情况必须要用被动式，否则，意思不同。比较：
She is too ill to move. 她病得很厉害，动弹不得。
She is too ill to be moved. 她病得很厉害，经不住转移。
五、与so [such]…that结构的转换
1. The box is too heavy for me to carry.
→The box is so heavy that I can’t carry it.
→It is such a heavy box that I can’t carry it.
2. The child is too young to dress himself.
→The child is so young that he can’t dress himself.
→He is such a young child that he can’t dress himself.
注：有时还可与 not…enough to…转换，但此时要注意把原句型中的形容词改为相对应的反义词。如：
The child is too young to dress himself.
→The child is not old enough to dress himself.
六、too…to…有时可表示肯定意义
在以下几种情况，too…to…结构可以表示肯定意义，而不是否定意义：
1. 当不定式前有否定词修饰时。比较：
He is too foolish to understand this. 他太蠢，不会明白这一点。
He is too clever not to understand this. 他太聪明，不会不明白这一点。
2. 当副词too的前面有否定词修饰时。如：
It shouldn't take too long to root him out.
把他铲除掉应该不需要太长的时间。
《柯林斯高阶英汉双解学习词典》
Never too old to learn. 活到老学到老。(直译：永远不会太老而不能学习)
It’s never too late to stop smoking. 戒烟何时都不算晚。(直译：永远不会太迟而不能戒烟)
3. 当副词too后面修饰的形容词是happy 、glad, ready, pleased、easy等表示“积极”意义的词汇时。如：
I’m too glad to see you again. 又见到你我很高兴。
We are too ready to help you. 我们很乐意帮助你。
I shall be only too pleased to get home. 我要回到家里就非常高兴。
I shall be only too pleased to get home.
我要回到家里就非常高兴。
It was all too easy to believe it.
这太容易令人相信了。
《柯林斯高阶英汉双解学习词典》
I am only too happy to drive you to the store. 我非常乐意开车送你去商场。
注：这类句子中的too通常含有very之意，且too前通常会有only, just等副词修饰。
B. too adj for sth
例：These shoes are much too small for me.
我穿这双鞋太小了。
C.too adj a n.
例：This is too difficult a text for me. 这篇课文对我来说太难了。
注意，如果too修饰的形容词同时还修饰单数可数名词，则要按“too 形容词 a 名词 to”安排词序：
It is too good a chance to miss. 那机会真好，不容错过。
She is too polite a person to refuse. 她非常客气，不好意思回绝。
He’s too clever a man to say a thing like that in public. 他是个很聪明的人，绝不会在公开场合说那种话的。
D. can't … too 形容词 无论……也不为过
例：We cannot emphasize the importance of protecting our eyes too much.
我们再怎么强调保护眼睛的重要性也不为过。
