男，30岁，左大腿疼痛1年余，夜间或休息加重，口服止痛药可缓解，结合图像，最可能的诊断是（）

A.骨瘤

B.骨样骨瘤

C.骨软骨瘤

D.骨结核

E.骨脓肿

Each NCS woks as a type of（）, assisting controlling and monitoring telex and telephone network as quickly as possible.

A.switch operator

B.communication gateway

C.national operator

D.on-scene commande