—Fire is very useful to human!

—Yes, especially in winter a fire _____________warm.

A．used to keep

B．can be used to keep

C．is used to keeping

D．was used to keeping

关于原发性肝癌的叙述，下列哪项不恰当（）

A.大体病理形态可分为结节型、巨块型和弥漫型

B.有半数患者以肝区疼痛为首发症状

C.约30％的患者AFP为阴性

D.主要并发症有肝昏迷、上消化道出血等

E.肝移植是目前首选的、最有效的治疗方法