His lecture was so long and ________ that many people felt ________ and left before it ended.[ ]

A．boring; boring  

B．bored; bored

C．boring; bored    

D．bored; boring

严重低钾血症病人主要死于（ ）

A．心肌收缩性降低

B．心肌传导性降低

C．心肌自律性降低

D．肾功能严重障碍

E．呼吸衰竭