Landforms
Mountains are landforms higher than 2,000 feet or about 600 meters above sea level.山是海拔2000英尺(約600米)以上的地貌溪胶。
Hills are like mountains, but not as tall.山就像山泞坦，但沒有山高率拒。
Mountains are formed by forces deep within the Earth and are made of many types of rocks.山是由地球深處的力量形成的腰耙，由許多種類的巖石構(gòu)成履怯。
Rivers are streams of water that usually begin at mountains and flow into the sea.河流是水的溪流鸣峭，通常從山上開始流入大海榜旦。
Many early cities were built alongside rivers.許多早期的城市都建在河邊。
Most of the world's water is in the oceans, which are large bodies of salt water.世界上大部分的水都在海洋里谬运，海洋是大的咸水體。
The oceans are also an important source of oxygen.海洋也是氧氣的重要來源带膜。
Deserts are areas of land that receive little or no rainfall.沙漠區(qū)是很少或沒有降雨的地區(qū)吩谦。
The amount of rainfall in some deserts is so low that only a few plants can survive.有些沙漠的降雨量很低，只有少數(shù)植物能生存膝藕。
A valley is a low, relatively flat area between hills or mountains, often with a river running through it.山谷是山丘或山脈之間地勢較低式廷、相對平坦的地區(qū)，通常有河流流經(jīng)芭挽。
Some valleys are formed by flowing water, and others are formed by glaciers.有些山谷是由流水形成的滑废，有些則是由冰川形成的。
many?early?civilizations?development?near?rivers許多早期文明都是在河流附近發(fā)展起來的
