We’d better set off or it will be dark we know it.A. before B. afterC. when D. until

问题补充：

We’d better set off，or it will be dark we know it.

A. before

B. after

C. when

D. until

答案：

(答案→)A. before

B. after

C. when

D. until

解析：考查状语从句的连词。语境表示“还不等我们意识到”，用before引导状语从句表示“在……之前”。