高浓度氧疗是指吸入氧浓度()
A.35%~50%
B.60%
C.90%
D.>30%
E.>40%
参考答案:B
解析:高浓度氧疗是指吸入氧浓度>50%
The teacher told us that light _____ much faster than sound. [ ]
A travels
B. traveled
C. was
D. willbe
试述领导行为的基本理论与模型。