—It’s a long time _______ I drunk so much. 

—Yes, and what a pity it is since it will be a long time ______ we see each other again.

A before; since                B. when; when

C. since; before                D. when; then

挤压机开车时下列哪种叙述正确（）

A.先开主电机，然后开启动电机

B.先开启动电机，然后主电机

C.两电机同时开

D.只开启动电机