题目

    surprised me most      to see some of the village people seated on the benches at the end of the room.       A. What; was                                   B. What; were       C. That; was                                    D. That; were 答案：A在一密闭容皿中，用等物质的量的A和B发生如下反应：A(g)＋2B(g)2C(g)反应达到平衡时，若混合气体中A和B的物质的量和与C的物质的量相等，则这时A的转化率为 [　　] A．40％B．50％ C．60％D．70％