A:①②③
B:②③④
C:①③④
D:①②③④
—When did your father stop smoking?
—In 1999, the year I was born.
若数a的近似数为1.6,则下列结论正确的是( )
如图是某同学设计的冶炼铁的实验装置,下列有关说法中正确的是( )