It was about 5 o’clock in the afternoon they had their supper.A. thatB. whatC. beforeD. w

问题补充：

It was about 5 o’clock in the afternoon they had their supper.

A. that

B. what

C. before

D. when

答案：

A. that

B. what

C. before

(答案→)D. when

解析：考查状语从句。When连接时间状语从句，句意：当他们吃晚饭时大约是下午五点钟。