In the 20th century, machines are run mostly by electricity. Two hundred years ago electricity was not in common use. Machines were often run by water, and therefore many factories grew up by running rivers. Today, however, factories can be placed far from our rivers.
在20世紀(jì)，機器大都是電動的。兩百年前，電還沒有廣泛的應(yīng)用，機器都是靠水力發(fā)動，因此，工廠都是開在流動的江河邊。然而，現(xiàn)今的工廠可以開在遠(yuǎn)離河流的地方。
在20世紀(jì)，機器大都是電動的。兩百年前，電還沒有廣泛的應(yīng)用，機器都是靠水力發(fā)動，因此，工廠都是開在流動的江河邊。然而，現(xiàn)今的工廠可以開在遠(yuǎn)離河流的地方。