问题
选择题
The other day ,my father drove his car at _____I thought was a dangerous speed.
A．as
B．that
C．what
D．which
答案
答案：C
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