引起Ⅱ型呼吸衰竭最重要的机制是（）
A.弥散功能障碍
B.通气量下降
C.氧耗量增加
D.通气／血流比例失衡
E.分流
参考答案：B
The old lady _________when I was in the countryside is said to be still very much alive though in her nineties.
A．after whom I looked
B．whom I took care
C．who I looked after
D．of whom I took care
以下（）故障不会引起中达开关电源系统的整流告警？
A、蓄电池温度过高
B、整流模块故障
C、室内温度过高
D、直流电压过低
