— Your silence    on recent events surprises me.    

— I think it's better____too little than say too much.    [ ]

A. say    

B. to say    

C. saying    

D. to be saying

诊断心律失常最常规的无创检查是（）

A.心电图

B.心电向量图

C.心音图

D.运动试验

E.超声心动图