We experience different forms of the Sun’s energy every day. We can see its light and feel its warmth. The Sun is the major source of evaporation of water from the oceans and lakes. Sunlight also provides the energy used by green plants to make their own food. These green plants then provide food for all organisms on the Earth.
我们每天都会接收各种形式的太阳能量，可以看见光，感受温暖。太阳是海洋和湖泊水蒸发的主要来源，还为绿色植物提供阳光用于制作食物，这些绿色植物为地球上的所有生物提供食物。
Much of the energy that comes from the Sun never reaches the Earth’s surface. It is either reflected or absorbed by the gases in the upper atmosphere. Of the energy that reaches the lower atmosphere, 30% is reflected by clouds or the Earth’s surface. The remaining 70% warms the surface of the planet, causes water to evaporate, and provides energy for the water cycle and weather. Only a tiny part, approximately 0.023%, is actually used by green plants to produce food.
来自太阳的大部分能量从未到达地球表面，被上层大气中的气体反射或吸收。在到达低层大气的能量中，30%被云层或地球表面反射，剩下的70%使地球表面变暖，使水蒸发，并为水循环和天气提供能量。只有一小部分（约0.023%）被绿色植物用于生产食物。
Many gases found in the atmosphere actually reflect heat energy escaping from the Earth’s surface back to the Earth. These gases act like the glass of a greenhouse in that they allow energy from the Sun to enter but prevent energy from leaving. They are therefore called greenhouse gases.
在大气中发现的许多气体实际上将从地球表面逸出的热能反射回地球。这些气体就像温室的玻璃一样，允许来自太阳的能量进入，但阻止能量离开。因此，它们被称为温室气体。
When sunlight strikes an object, some of the energy is absorbed and some is reflected. The amount reflected depends on the surface. For example, you’ve probably noticed how bright snow is when sunlight falls on it. Snow reflects most of the energy from the Sun, so it contributes to the low temperatures of winter. Dark-coloured surfaces, such as dark soil or forest, absorb more energy and help warm the surrounding air.
当阳光照射物体时，一部分能量被吸收，另一部分被反射，反射量取决于物体表面。例如，你可能已经注意到当阳光照射到雪上时，雪是多么明亮。雪反射了大部分来自太阳的能量，所以它是造成冬季低温的原因之一。深色的表面，如深色的土壤或森林，会吸收更多的能量，有助于温暖周围的空气。
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