________in the queue for half an hour，Tom suddenly realized that he had left his wallet at home.

[ ]

A．To wait  

B．Have waited

C．Having waited  

D．To have waited

根据血气分析结果，该患者的呼吸功能障碍为

A．通气功能障碍

B．换气功能障碍

C．通气和换气功能障碍并存

D．肺泡膜增厚所致弥散功能降低

E．通气/血流比例增高