A:Mg2+ Cl﹣ Cu2+ NO3﹣
B:H+ CO32﹣ K+ SO42﹣
C:Ba2+ Cl﹣ NO3﹣ Na+
D:NH4+ HCO3﹣ Al3+ SO42﹣
如图所示,闭合开关S,线圈周围的小磁针,静止时指向正确的是( )
如图,等腰三角形ABC中AB=AC=5,BC=6.
有关地球基本面貌特征的描述,正确的是( )
Look out! You should_______ careful _______ everything around you. It's dangerous!