A.Children have to walk longer distances to school.
B.The education system has got much worse.
C.Things aren’t as hard as they once were.
D.It hasn’t changed much at all.

A.Children have to walk longer distances to school.
B.The education system has got much worse.
C.Things aren’t as hard as they once were.
D.It hasn’t changed much at all.

A.
B.
C.
D.

A.
B.
C.
D.

A.4,32.
B.43,2.
C.21,6.
D.2,16.

A.xiđerit, hemantit đỏ, manhetit.
B.pirit, hemantit nâu, manhetit.
C.hemantit, pirit, manhetit.
D.xiđerit, manhetit, hemantit nâu.

A.glucozơ.
B.fructozơ.
C.mantozơ.
D.saccarozơ.

A.C + O2 → CO2.
B.C + H2O → CO + H2.
C.3C + 4Al → Al4C3.
D.C + 2CuO →2Cu + CO2.

A.Tính dẻo.
B.Tính dẫn điện.
C.Tính cứng.
D.Ánh kim.

A.NaI.
B.KCl.
C.NaCl.
D.NaBr.