临床上常作为辨认椎骨序数的标志是（） A.寰椎 B.枢椎 C.第六颈椎 D.隆椎 E

—Would you please help me ______, Wang Fei? This question's too hard for me.

—OK. Let me try.      [ ]

A. after  

B. up        

C. out        

D. with

It is reported that many a new house ______ at present in the disaster area.

A．are being built

B．were being built

C．was being built

D．is being built

最著名的脱胎漆器产自（）。

A.北京

B.扬州

C.广州

D.福州

十、五、三车距离信号，表示推进车辆的前端距被连挂车辆的距离。

显示交换表命令的使用方法，在交换机的超级用户模式下，大中型交换机输入命令( )。

A．show cam

B．show cam dynamic

C．show cam-address-table

D．show mac-address-table