A:1 mol氧气
B:17 g氨气
C:标准状况下44 g二氧化碳
D:0℃、2×105 Pa时2 g氢气
The naughty boy is always in his room.His mother is very angry.
“红军不怕远征难,万水千山只等闲。”当年红军“远征”的直接原因是