【新编英语教程】（第一册）Unit4 资源(2/6)

英语自学网

注意首字母的大小写，不含标点符号
__1___ had been used for hundreds of years to operate ___2___ and to pull carts, wagons, and other vehicles.
The sun's energy takes water from rivers, lakes, and oceans and returns it to the earth ___3___or snow. When rain or snow falls ___4___, some of it flows into rivers and streams.The energy from animals
farm equipment
in the form of rain
on the land