单项选择题
A.1.5~2.5L/minB.2~3.5L/minC.2.5~3.5L/minD.3~4.5L/min
A.6~7L/minB.5~7L/minC.5~8L/minD.4〜6L/min
A.20mmHgB.30mmHgC.40mmHgD.50mmHg