A.1 B.2 C.3 D.4
A.C10(Cb10) B.Cl5(Ch15) C.C20(Cb20) D.C25(Cb25)
A.不應(yīng)大于 B.不應(yīng)小于 C.不應(yīng)小于2/3 D.不應(yīng)大于2/3