单项选择题
A．0 B．0.9 C．1.0 D．6.3
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)]