A:SO2
B:NH3
C:Cl2
D:O2
--- What do you think of the dress?--- Wonderful. I don't think I can find a ________ one.
粮店有大米20袋,面粉50袋,共重2250千克,已知1袋大米的重量和2袋面粉的重量相等,那么一袋大米重____ 千克。