2011年东北三省四市统一考试暨沈阳市高三教学质量监测 We should do what we have to do ______ we can do what we want to do in the future. A. so that B. in case C. for fear that D. now that 答案:A
已知下列热化学方程式: ①H2(g)+1/2O2(g)=H2O(g) ΔH1=a kJ·mol-1 ②2H2(g)+O2(g)=2H2O(g) ΔH2=b kJ·mol-1 ③H2(g)+1/2O2(g)=H2O(l) ΔH3=c kJ·mol-1 ④2H2(g)+O2(g)=2H2O(l) ΔH4=d kJ·mol-1 下列关系式中正确的是( ) A.a<c<0 B.b>d>0 C. 2a=b<0 D.2c=d>0