单项选择题
A.聚丙烯 B.聚乙烯 C.聚四氟乙烯 D.聚氯乙烯
A.Rs+[rbe+(1+β)RE]∥RB B.(Rs∥RB) ∥[ rbe+(1+β)( RE∥RL] C.RB∥[rbe+(1+β)RE] D.RB∥[ rbe+(1+β)( RE∥RL)]
A.双向弯曲 B.弯扭组合 C.压弯组合 D.压、弯、扭组合