I ________ sooner but I didn’t know that they were waiting for me.

A．had come  

B．was coming

C．would come  

D．would have come

二维超声心动图诊断二尖瓣狭窄的主要依据是（）

A.瓣口开放面积变小

B.瓣叶增厚

C.腱索粗大

D.瓣膜活动受限

E.左房明显增大