对气道阻力影响不大的因素是（）
A.气体流速
B.气道口径大小
C.气道物理形状
D.气道内分泌物聚积
E.身高
参考答案：E
新生儿室湿度应维持在()。
A．40%～50%
B．45%～55%
C．50%～65%
D．55%～65%
E．60%～65%
—Hello! Can I speak to Tom?
—Sorry. He isn't in now. He____to play tennis. [ ]
A. goes
B. will go
C. has gone
D. was going
