Ⅱ型呼吸衰竭,PaCO必须大于()
A.70mmHg
B.45mmHg
C.65mmHg
D.50mmHg
E.60mmHg
参考答案:D
Helen always helps her mother even though going to school _____ most of her day. [ ]
A. takes up
B. makes up
C. saves up
D. puts up
孕妇需避免X线检查,是因为()
A.X线的光化学效应
B.X线的荧光作用
C.X线的生物效应
D.X线的感光作用
E.以上都不是