横向
1
Large natural elevation of earth
5
Line dividing two countries
7
Largest river in South America
8
Flat grassland in tropical regions
10
Low area between mountains
11
Distance east or west of prime meridian
纵向
2
One of seven major landmasses
3
Largest hot desert in the world
4
Seasonal heavy rainfall
6
Wearing away of land by water or wind
9
Largest ocean on Earth
12
Land surrounded by water on three sides