呼吸监测最直接的指标是（）
A.呼吸频率
B.有无发绀
C.血氧饱和度
D.血气分析
E.肺功能测定
参考答案：C
按体积算在空气含量最多的是[ ]
A．氧气
B．稀有气体
C．氮气
D．二氧化碳
—Could you please tell me ______ in America?
—On the fourth Thursday in November. [ ]
A. when is Thanksgiving Day
B. when Thanksgiving Day is
C. what we eat on Thanksgiving Day
D. what do we eat on Thanksgiving Day
