— I don't know          makes her different from others.    

— Confidence, I think.[ ]

A. how is it that  

B. how it is that    

C. what is it that    

D. what it is that

超声检查 * * 肌功能不全，最常见的表现是（）

A.M型超声可见二尖瓣CD段呈吊床样改变

B.二尖瓣及腱索完整

C.二尖瓣向左心房脱垂，呈连枷样运动

D. * * 肌回声可增强或减低

E.彩色多普勒显示二尖瓣反流