题目

By the end of last year, another new gymnasium __________ in Beijing. A. would be completed               B. was being completed   C. has been completed               D. had been completed   答案：D20．已知：①CaO（s）+H2O（1）═Ca（OH）2（s）；△H1②CaO（s）+2HCl（g）═CaCl2（s）+H2O（1）；△H2③NH3（g）+HCl（g）═NH4Cl（s）；△H3④Ca（OH）2（s）+2NH4Cl（s）═CaCl2（s）+2NH3（g）+2H2O（1）；△H4下列关于上述反应焓变的判断正确的是（　　）A．△H1＜0，△H3＞0B．△H1＞△H4C．△H4=△H2-△H1-2△H3D．△H4-△H1-△H2＜0