— Look, that’s Tom—the lost boy!

— It’s really_______great comfort to see him safe again. He is sure to bring_______comfort to his worried mother.

A．a; a

B．the; the

C．a; /

D．the; /

青年男性，颊侧牙龈溃疡3个月，经两周抗炎治疗不愈。为明确诊断，应选用的检查为（）

A.牙片

B.CT

C.B超

D.切取活检

E.细针吸活检