The idea he didn’t have to stop at the red light at night caused the traffic accident.A.

问题补充：

The idea he didn’t have to stop at the red light at night caused the traffic accident.

A. that

B. which

C. what

D. why

答案：

(答案→)A. that

B. which

C. what

D. why

解析：考查同位语从句：同位词是the idea，后面是对idea的内容进行说明，是同位语从句，用that连接，that不做成分，也不能省略。句意：他在夜里不用等红灯的想法导致了交通事故。选A。