The speed Tom drives his car is too high.A. in which B. at which C. at that D. in what

问题补充：

The speed Tom drives his car is too high.

A. in which

B. at which

C. at that

D. in what

答案：

A. in which

(答案→)B. at which

C. at that

D. in what

解析：考查定语从句中关系词与介词的连用。定语从句中关系词前面的介词有3个来源：先行词的固定搭配，定语从句中的固定搭配：句子的语义；本题的先行词与介词at是固定搭配。at the speed of以…的速度；句意：Tom开车的速度太快了。故B正确。