单项选择题
A.15mm B.25mm C.20mm D.30mm
A.tmin=120+0.01d B.tmin=100+0.01d C.tmin=100+0.1d D.tmin=120+0.1d
A.fak<100Kpa B.fak<180Kpa C.fak<200Kpa D.fak<150Kpa