（）开始成形时，升降台的工作面处于液面下—个薄片的深度，激光束按工件的最下—层薄片的

Tony caught up with me and it was ______ great comfort to me to have ______ company for it is dangerous to walk alone at midnight.

 [      ]

A. a; a

B. a; /

C. /; /

D. the; the

一条水渠长4千米，把它画在比例尺是1：500000的图纸上，应画多少厘米？

John opened the door. There ________ he had never seen before.[ ]

A. a girl did stand  

B. a girl stood

C. did a girl stand  

D. stood a girl

在《日出》中，没出场的黑社会老大是()。

解放战争时期为了适应部队需要，各野战军和地方部队的各级政治部都建立了“（）”。