Mother was so angry at allI was doingshe walked out.A. that；thatB. what；thatC. what；asD. t

问题补充：

Mother was so angry at allI was doingshe walked out.

A. that；that

B. what；that

C. what；as

D. that；which

答案：

(答案→)A. that；that

B. what；that

C. what；as

D. that；which

解析：首先通过分析句子结构，可知这个句子中包含一个状语从句和一个定语从句，其中定语从句的先行词是不定代词all，所以只能用that；so … that… 如此……以致，是状语从句的固定句式，故选A。