横向
1
Vast body of salt water
4
One of seven major landmasses
6
Flat grassland in tropical regions
8
Line dividing two countries
9
Wearing away of land by water or wind
13
Steep rock face at edge of land
纵向
2
Land surrounded by water
3
Seasonal heavy rainfall
5
Region surrounding the North Pole
7
Large slow-moving mass of ice
10
Largest ocean on Earth
11
Deep narrow valley with steep sides
12
Narrow sea inlet between cliffs