—Hey, who’s that man over there? He    us since we came in.

—The one by the door? I don’t know. He looks like a lawyer or something, not a journalist. Perhaps he      here to look round, like us.

A．has watched；only came

B．is watching；had only come

C．has been watching；has only come

D．had been watching；came

男性，55岁，4个月来乏力、头晕，血红蛋白80g/L，平均红细胞体积59fl，平均红细胞血红蛋白浓度28%，网织红细胞计数4%，血清铁450μg／L，总铁结合力4800g/L。既往体健。

应首先作的最简单的检查是（）

A.尿常规

B.腹部B超

C.大便潜血

D.消化道钡餐检查

E.胃镜检查