such 是形容词，修饰名词或名词词组，so是副词，只能修饰形容词或副词。so 还可与表示数量的形容词many，few，much， little连用，形成固定搭配。

so + adj. such + a(n) + n.

so + adj. + a(n) + n. such + n. (pl.)

so + adj. + n. (pl.) such +n. (pl.)

so + adj. + n. (不可数)such +n.(不可数)

so foolish such a fool

so nice a flower such a nice flower

so many/ few flowers such nice flowers

so much/ little money. such rapid progress

so many people such a lot of people

so many 已成固定搭配，a lot of 虽相当于 many，但 a lot of 为名词性的，只能用such搭配。so…that与such…that之间的转换即为 so与such之间的转换。