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

问题描述:

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
选一个
谢谢啦

C
显然后面是一个从句,throught后面的句子缺少主语,所以前面的空要填可以充当主语的词,所以排除A和B,而因为前面有一个at,所以不能加that,要加what.