A.3 B.9 C.12 D.16
A.5.0MPa B.設(shè)計(jì)強(qiáng)度的100% C.設(shè)計(jì)強(qiáng)度的70% D.3.0MPa
A.1:2.5 B.1:2 C.1:4 D.1:3