缩窄性心包炎（）。
A.肺性发绀
B.心性混合性发绀
C.淤血性发绀
D.缺血性发绀
E.混合性发绀
参考答案：C
I was not quite sure __________.
A．what is she looking for
B．why she came late for school
C．how did she deal with the problem
D．if she has arrived
简单面罩供氧流量为6L/min，吸入氧浓度为（）
A.24%～32%
B.28%～36%
C.32%～40%
D.38%～46%
E.46%～56%
