题目

—Do you like skating? —Yes, skating is a good way _______. A. to keep health   B. to keep healthy   C. keeping healthy  D. keep healthy 答案：B在一定温度下，向某恒容的密闭容器中加入1 mol N2和3 mol H2，发生反应：N2(g)＋ 3H2(g)2NH3(g)。此反应达到平衡的标志是(　　)A. N2、H2和NH3三者共存 B. 容器内气体的浓度不再发生变化C. N2、H2和NH3的物质的量浓度相等 D. 单位时间消耗0.1molN2的同时生成0.2 mol NH3