5.6g含有杂质的铁片加到足量的稀硫酸中,共收集到0.19g氢气,该铁片中不可能含有的杂质是()
A:铝和铜
B:镁和锌
C:锌和铜
D:镁和铝
一元二次方程x2=2x的根是( )
We'll have an English singing show on November____(4th/14th).