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

问题补充：

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

A. as

B. that

C. which

D. what

答案：

A. as

B. that

C. which

(答案→)D. what

解析：考查宾语从句。I thought是插入语，可以省略。What I thought was a dangerous speed是介词at的宾语，what在句中做主语。句意：前一天，我的父亲以一个我认为非常危险的速度开车。