下列属于化学变化的是( )
A:滴水成冰
B:蜡烛成灰
C:木已成舟
D:铁杵成针
① ② ③ ④
小宏同学坐在行驶的汽车里,如果说他是静止的,则所选择的参照物是()
____ (happiness) can make us become ill, so we should try our best to be happy.