--How many ________（大洲）are there in the world? 

--Seven.

The capital of ________（俄罗斯）is Moscow.

Oceans covers ________（四分之三）of the earth's surface.

English and French are ____________（官方语言）in Canada.

Is the elephant largest animal on ________（陆地）?

The world's longest river is ________（尼罗河）in Africa.

Deserts cover one-fifth of the earth's ________（表面）.

________（南极洲）is the coldest and driest continent in the world.

The biggest ocean in the world is ________（太平洋）.