鼻导管吸氧时所能提供的FiO2范围是
A．0．2～0．4
B．0．2～O．6
C．0．4～O．6
D．0．6～0．8
E．0．4～0．8
参考答案：A
This job is ______ doing, but it isn’t ______ to spend so much time on it.
A．worth; worth
B．worth; worthwhile
C．worthwhile; worth
D．worthwhile; worthwhile
最常见的先天性心脏病是（）
A.房间隔缺损
B.法洛四联症
C.室间隔缺损
D.肺动脉狭窄
E.动脉导管未闭
