The first thing I am going to do this evening is to go to sleep.A. what B. thatC. whichD.

问题补充：

The first thing I am going to do this evening is to go to sleep.

A. what

B. that

C. which

D. who

答案：

A. what

(答案→)B. that

C. which

D. who

解析：句意：我今晚要做的第一件事就是去睡觉。在定语从句中，先行词被形容词最高级或序数词修饰时应用that。故选择B。