例题:Tom is _so_ good a student _as_ is often praised by the teacher. Jack is _so_ smart a boy _that_ he can work out difficult maths problems quickly. 如何区分so...as和so...that?
so……as中as必须在 从句 中担任成分(主语、宾语等),而从句就是我们熟悉的 定语从句 咯。 so……that中的that 不能在从句中担任成分,只是单纯的 先行词 ,从句也就不算定语从句了。 简单的说,要判断使用哪一个,可以看先行词在从句中是否担任成分,如 例句 中as是is often praised by the teacher的主语,指代a student.而第二句中he can work out difficult maths problems quickly本身就是一个 完整的句子 。 谢谢