下列各组热化学方程式中，化学反应的△H前者大于后者的是
①C(s)＋O2(g) = CO2(g)；△H1 C(s)＋
O2(g) = CO(g)；△H2
②S(s)＋O2(g) = SO2(g)；△H3 S(g)＋O2(g) = SO2(g)；△H4
③H2(g)＋O2(g) = H2O(l)；△H5 2H2(g)＋O2(g) = 2H2O(l)；△H6
④CaCO3(s) = CaO(s)＋CO2(g)；△H7 CaO(s)＋H2O(l) = Ca(OH)2(s)；△H8
A．① B．④ C．②③④ D．①②③