A.30KN B.35KN C.40KN D.45KN
A.2、0.2 B.1、0.1 C.2、0.1 D.1、0.2
A.0.005kN/㎡ B.0.01kN/㎡ C.0.015kN/㎡ D.0.02kN/㎡