题目

已知：2CO(g)+ O2(g)    2CO2(g)   △H=-566kJ·mol-1N2(g)+O2(g)    2NO(g)   △H=+180kJ·mol-1 则2CO(g)+2NO(g)    N2(g)+2CO2(g) 的△H是    A．-386 kJ·mol-1                            B．-746 kJ·mol-1              C．+386 kJ·mol-1                            D．+746 kJ·mol-1  答案：B解析:略 If we work with a strong will, we can overcome any difficulty, ___ great it is.A. what B. how C. however D. whatever