题目

My teacher takes great trouble __________me learn English, since I have a lot of trouble _________it. A . helping; learning B . to help; to learn C . helping; to learn D . to help; learning 答案：D下列各组中的两个反应，前一个反应放出的热量比后一个反应放出的热量多的是（反应物参与反应的物质的量均按化学方程中的化学计量数计算，且g、l、s分别表示物质的状态为气、液、固态）① 2H2(g)+ O2(g) = 2H2O(g)        2H2(g)+ O2(g) = 2H2O(l)   ② C(s)+ O2(g) = CO2(g)           C(s)+ O2(g) = CO(g)A.只有①B.只有②C.①②D.①②都不符合题意