The other day ,my father drove his car at I thought was a dangerous speed.A. asB. thatC. w

The other day ,my father drove his car at I thought was a dangerous speed.
A. as
B. that
C. what
D. which

A. asB. that(答案→)C. whatD. which解析：考查连词，根据句子结构可知，该句为宾语从句，作at的宾语，从句中缺少was的主语，因此选择what，as 用于定语从句和状语从句，that在宾语从句中不做成分which用于有范围的选择

就是这个解释