已知下列反应的热化学方程式: ① C(金刚石,s) + O2(g) === CO2(g) ΔH1 ② C(石墨,s) + O2(g) === CO2(g) ΔH2 ③ C(石墨,s) === C(金刚石,s) ΔH3=1.9 kJ/mol 则下列说法正确的是 A.石墨转化成金刚石的反应是吸热反应 B.金刚石比石墨稳定 C.ΔH3=ΔH1-ΔH2 D.ΔH1>ΔH2---How many elephants are there in the zoo?--- There aren’t _______.A.someB.anyC.oneD.much