3hv 2=2h = hv E。=0 ●●● ●● C .=c3 3=C4C1 4!/(1!3:)=4:/(3!1!)=4/(2!1!1:) 120 2 3 0 1 2 3 = = = =        h h h t 1 = C4 1 =4!/(1!3!) =4 t 2 = C4 3 =4!/(3!1!) =4 t 3 = C4 1 C3 1 = 4!/(2!1!1!) =12