A.inequalities
B.developments
C.advantages
D.outcomes

A.most of the world's urban expansion is taking place in slums
B.too many people hope for a better life in cities
C.employment opportunities in cities are greater
D.poverty cannot be eliminated thoroughly

A.NaAlO2.
B.AlCl3.
C.Al2O3.
D.Al2(SO4)3.

A.Na, K.
B.Be, Na.
C.Cr, K.
D.Na, Fe.

A.Na.
B.Ca.
C.Al.
D.Fe.

A.Mg2+.
B.Ag+.
C.Fe2+.
D.Cr2+.

A.Ca.
B.Na.
C.Cu.
D.Al.

A.Cu.
B.Al.
C.Fe.
D.Mg.

A.Tính khử.
B.Tính oxi hóa.
C.Tính axit.
D.Tính bazơ.

A.Al, Fe.
B.Au, Pt.
C.Al, Au.
D.Fe, Pt.