When the elevator doors open stand aside and let everyone out you try to get in.A. unles

问题补充：

When the elevator doors open, stand aside and let everyone out you try to get in.

A. unless

B. although

C. until

D. before

答案：

A. unless

B. although

C. until

(答案→)D. before

解析：考查连词：A. unless 除非B. although虽然C. until直到D. before在…前面，…才…,句意：当电梯门打开的时候，要站在一边，让大家出来你才能进去。选D。