题目

将a g由CO和H2组成的混合气体在足量的O2中充分燃烧后，将生成的所有产物通过足量的Na2O2固体，Na2O2固体增加的质量为 A．a g                                  B． g C． g                                D． g 答案：A从方框中选择恰当的介词填空at, for，with, around, about1. They are talking      when    to have a meeting.2. I want to make friends      you.3. I stay      home    to    do homework today.4. If I have enough money，I will travel      the world.5.       the    games，I think people should get gifts if they win.