No sound and no voice______ for a while.

A．have heard

B．has heard

C．has been heard

D．have been heard

慢性胆囊炎的CT征象不包括（）

A.胆囊壁较均匀增厚

B.胆囊壁钙化

C.胆囊扩张或缩小

D.胆囊周围可见低密度环影

E.胆囊内有结石影