单项选择题
A.Idz·j=KkKjx B.Idz·j=KkKjx C.Idz·j=KkKjx D.Idz≤
A.Ir= B.Idz=Kk(Ktx△f+△U+△f')Ik·max C.II·dz·j= D.Km·min=≥2