A.KB B.KG C.KMl D.A和C
A.1.0 B.1.2 C.1.5 D.1.76
A.1/12λb*b*b B.1/36λb*b*b C.1/48λ(b1+b2)(b1*b1+b2*b2) D.1/48λb*b*b