—Can you believe I paid 15 yuan for these three apples?
—You should try the supermarket________I went yesterday.Fruits there are cheap.
—How was your recent trip to Sichuan? —I've never had_______ one before.
某化学兴趣小组的同学对实验室制取CO2及相关性质进行一系列的探究活动．
当AB型血的人失血过多，抢救时应该给他输入（ ）
