such与so的意思都是“如此，这样”。但两者用法根本不同。
1、such后面主要是修饰名词。即：such＋a/an＋adj.＋n.。如果名词是不可数名词或复数名词，则不可以用不定冠词a或an。如：
①He has such a beautiful kite.
②The garden has such fresh air.
2、so后面只能跟形容词或副词。即：so＋adj.或adv.如：
①The tiger is so big. And the cat is so small.
3、它们后面还可以与that连用，that引导的是结果状语从句。即：such…that 和so…that意思是“如此……以致于……”。要注意so后的中心词是形容词，such后的中心词是名词，如：
①His brother is so young that he can't go to school.
②She is such a clever girl that she can make much progress in math exam.
注：当名词前有many，much修饰时，不用such，用so，如：
①There were so many people that we could hardly move on.
②I ate so much food that I didn't want to go anywhere.
.①He spoke so fast that we could not understand him.
②They are such delicious cakes that I want to eat another two.
③It is such an interesting story that I want to read it again.
