The old man sat in front of the television every evening, happy ________ anything that happened to be on.[    ]

A. to watch  

B. watching

C. watched  

D. to have watched

进行呼气末二氧化碳分压监测时，下列哪项不需要具备的：（）

A.二氧化碳检测模块

B.监护仪

C.二氧化碳传感器

D.气管插管或气管切开

E.患者意识清楚