1. so...that意为“如此……以至于……”, so为副词,后面跟形容词或副词,that引导一个表示结果的状语从句。如:
    She was so happy that she jumped.
    He spoke so fast that I could hardly follow him.
2. such... that与so... that意思相同,that后引导的也是一个表示结果的状语从句,但such为形容词,后面跟名词,并且名词前常有冠词、形容词等修饰。如:
    I have never seen such a big cat. 
    It is such bad weather that we have to stay at home all day.
    They are such interesting stories that all the children like reading them.
【提示】
a. such+a(an)+adj.+n.=so+adj.+a(an)+n. 如:
    She is such a lovely girl.=She is so lovely a girl.
b. 当many / much / little / few表示“数量多少”修饰名词时,前面用so而不用such。但当little不表示数量“少”而表示“小”时,则仍用such。如:
    There is so little water in the pool that we can’t swim at all.
    He is such a little baby that I have to look after him all day.
3. too... to意为“太……不能……”, too为副词,后面跟形容词或副词,to引出动词不定式,在不定式的前面还可以由for引出其逻辑主语。如:
     The box is too heavy for you to carry.
     I got up too late this morning to catch the train.

【提示】
a. 当too后跟的是glad, kind, ready, easy, pleased, willing等词时,too... to结构并不表示否定的意思。如:
     I’m too pleased to receive your letter. 收到你的来信,我太高兴了。
b. 当it代替后边的不定式短语,用作句子的形式主语时,并不等同于上面的too... to结构。如:
     It’s too dangerous for the child to play in the street.
c. 含有too... to结构的句子常常可以用so... that, such... that或enough to结构来改写。如:
     His handwriting is too bad for me to read the letter fast. →
     His handwriting is so bad that I can’t read the letter fast.
     His handwriting is not good enough for me to read the letter fast.
注意:too... to结构与so... that或such... that结构互相改写时,要避免句子成分的缺失或重复。如:
【正】The bag is so heavy that I can’t carry it.
【误】The bag is so heavy that I can’t carry.
【正】The bag is too heavy for me to carry.
【误】The bag is too heavy for me to carry it