单项选择题

A.开刀前MVV(maximum voluntary ventilation)=90﹪预测值
B.开刀前FEV1(forced expiratory volume in 1 second)=50﹪预测值
C.开刀前FVC(forced vital capacity)=80﹪预测值
D.开刀前FEV1/FVC=70﹪