so that和such that用法详解：
1.so that以便；表示【目的】
常与情态动词连用：
现在和将来时态可用can/may/will/shall等
过去时态可用could/might/would/should等

I will go to the library so that I can study quietly. 
我会去图书馆，以便我能够安静地学习。
I bought a map so that I wouldn’t get lost. 
我买了一张地图，那样我就不会迷路了。
We got to the movie theatre early so that we could get good seats. 
我们早早来到电影院以便能够有好位置。


2.so…that…如此…以致；表示【结果】
1) so + adj./adv. + that…： 如此…以致…
She was so tired that she could hardly speak. 
她是如此累，以致几乎无法讲话。
He walked so fast that he fell down on the ground. 
他走的太快了，以致摔倒在地。

2)so + adj. + a/an + n.+ that….：如此…以致…
She was so clever a girl that she could understand. 
她是如此聪明的一个女孩子， 她会明白的。
[ a/an+可数名词单数 ]

It was so interesting a book that I read it twice. 
这本书是如此有趣，以致我读了两次。

3)so + many/much +n. + that…: 如此…以致…
There are so many people that I can’t find him. 
人太多了，以致我找不到他。
[many + 可数名词复数]

He drank so much water that he threw up. 
他喝太多水了，以致呕吐了。
[much + 不可数名词]

3.such…that.. 如此…以致；表示【结果】
1)such + a/an + adj. +n. + that  
=  so + adj. + a/an + n.+ that 
[注意adj.的位置，a/an+可数名词单数]

She was such a clever girl that she could understand. 
她是如此聪明的一个女孩子， 她会明白的。
=She was so clever a girl that she could understand. 

It was such an interesting book that I read it twice. 
这本书是如此有趣，以致我读了两次。
=It was so interesting a book that I read it twice.

2）such + adj. +可数名词复数/不可数名词 +that
They are such smart boys that they can do it. 
他们是如此聪明的男孩子，他们能做到的。
They were in such pain that they were unable to move. 
他们是如此疼痛，以致无法动弹。
[pain在此是不可数名词，前面无a/an]

注：such后跟名词复数情况下则不可与so替换
She made such stupid decisions that she could get fired. (√)
She made so stupid decisions that she could get fired. (×)

4.such不可后跟many/much/few/little等，so才可以
She had so much work that she had to stay up all night. （√）
She had such much work that she had to stay up all night. （×）

注意：若little不是表示量，而是表示“小”的含义，则可与such连用
He is such a little boy that he can’t understand.
他是如此小的一个男孩子，（以致） 他是不会明白的。