银汞合金可塑性较大的时间范围为()
A.5~9分钟
B.10~14分钟
C.15~20分钟
D.21~25分钟
E.26~30分钟
参考答案:C
正常人过度通气后可以出现呼吸暂停其主要原因是()
A.血PH升高
B.PaO2升高
C.呼吸机渡劳
D.PaO2降低
E.呼吸调整中枢抑制
If the outcome of event A is not affected by event B, then events A and B are said to be:()
A. mutually exclusive.
B. statistically independent.
C. collectively exhaustive.