题目

一定质量的气体，在温度保持不变的变化过程中，下列物理量发生变化的有A.分子的平均速率B.单位体积内的分子数C.气体的压强D.分子总数 答案：BC---Could you tell me ______?---Sorry, I don’t know. Please ask the clerk over there.A. that farmers grow rice in the southB. when will Laura show us the paper cuttingsC. where we can find a guide bookD. how did they achieve their dream