The teenage year from 13 to 19 were the most difficult time for me . They were also the best and worse years in my life . At the first, I thought I knew everything and could make decisions by yourself. However, my parents didn’t seem to think such. They always tell me what to do and how to do it. At one time , I even felt my parents couldn’t understand me so I hoped I could be freely from them. I showed them I was independent by wear strange clothes. Now I am leaving home to college. At last, I will be on my own, but I still want to have my parents to turn to whenever need help.

8（）

将盛有NO₂和O₂的混合气体的试管倒扣在水中，充分反应后，试管内充满溶液，则NO₂和O₂的体积比为

A．1：1

B．3：1

C．4：3

D．4：1