题目

 As Chinese President Xi Jinping put it in the 2015 New Year Message, those achievements _______ possible without the support of the people. A. had not been    B. would not have been     C. were not    D. would not be 答案：B在2SO2+O22SO3的反应里,开始SO2和O2的浓度均为0.5mol/L,2分钟后测得SO2的浓度为0.25mol/L,则=_____________________，各物质所表示的反应速率的最简整数比::=_________