Question

The other day, my brother drove his car down the street at ________ I thought was a dangerous speed.

A. as

B. which

C. what

D. that

 

Answer 1

答案：C
解析：

at是介词，后面所跟的是一个介词宾语从句，I thought是宾语从句中的主句，后面所跟又是一个宾语从句，所填之词一是要能引导宾语从句，二是还要能在宾语从句中作主语，这是what的典型用法。