A:插入带火星的木条
B:观察气体颜色
C:闻气体的气味
D:倒入澄清石灰水
你想说老鼠的尾巴很长,可以说:
Fire can____ down a lot of trees. It can____ people, too. We must be____with fire. We mustn't____ in the forest. We mustn't play____ fires at home. We mustn't play with matches either.