Introduction
Scientists think that the water we drink, bathe in, and use to grow crops has been here on Earth since long before the time of the dinosaurs. It has just been moving around and around in the atmosphere in an endless cycle called the water cycle.
介绍
科学家们认为，早在恐龙时代以前，供我们饮用、洗澡、浇灌农作物所用的地球之水，一直在大气中不停地运动，我们将这种现象称之为水循环。
The water cycle
水循环
Expanse
Water covers more than 70 percent of the Earth's surface in the form of oceans, rivers and lakes.
扩展
水以江河湖海的形式存在于地球，占了70%多的地球表面。
Evaporation
The heat from the sun causes some of the water to evaporate or turn into water vapor or gas. This water rises from rivers, lakes and the oceans and goes into the air.
蒸发
来自太阳中的热量蒸发了部分水量，或将其变成了水蒸气。河流、湖泊及海洋中的水以蒸气的形式进入大气层。
condensation
As the water vapor cools in the air, it condenses. This means that it changes back into a liquid form. If you pour a cold glass of water on a hot day, you would notice condensation on the glass.
冷凝
水蒸气在大气中冷却，凝结。这意味着水蒸气又变回了液体形态。如果你在大热天倒一杯冷水，你会发现杯壁上出现的冷凝现象。
Precipitation
When so much water has condensed； the clouds become heavy and can't hold it anymore. The water then falls back to Earth as precipitation - rain, hail or snow.
降水
水凝结到一定程度时；云层会变得很重，难以将其固住。水就会重新降到地面，称为降水---即：雨水，冰雹或雪。
Runoff
Melted snow and rain that run downhill eventually end up in the oceans. The flow of water to the ocean is called runoff.
径流
雪水和雨水向下流动，最终汇入海洋。流入海洋的水流称为径流。
Saving water
Conserving water is easy and will not only help the environment but will probably save you money.
节约用水
节约用水很容易做到，这种行为不仅可以保护环境，还可能帮助你省钱。
