—It’s 9 o’clock now. I must go.—It’s raining outside. Don’t leave it stops.A. whenB. since

问题补充：

—It’s 9 o’clock now. I must go.

—It’s raining outside. Don’t leave it stops.

A. when

B. since

C. while

D. until

答案：

A. when

B. since

C. while

(答案→)D. until

解析：句意：现在是九点。我必须走了。外面在下雨。等雨停了再走。When当……的时候； since自从；while当……的时候； until直到，常用于句型not…until，所以选D.