横向
1
Low-lying land surrounded by higher ground
2
Cold treeless Arctic plain
4
Wearing away of land by water or wind
5
Goods brought in from another country
6
Land surrounded by water
8
Large area covered with trees
11
Area where water covers the soil
12
Total number of people in an area
纵向
2
Region near the equator
3
Height above sea level
7
Flat grassland in tropical regions
9
Steep rock face at edge of land
10
Largest ocean on Earth