Solar energy is one of the cleanest and most plentiful sources of energy. Solar power depends on sunlight, so in cloudy weather and at night, no power is generated.
太阳能是最干净，也是最丰富的能源之一。太阳能依赖于阳光，因此多云的天气或者夜晚不能产生能量。
Wind energy is non-polluting but is only useful in places where there is a lot of wind. Wind turbines convert the kinetic energy of the wind into mechanical power.
风能无污染，但是只适用于多风的地区。风力发电机将风的动能转化为机械能。
Nuclear energy is efficient and doesn’t produce carbon gases as a waste product. The dangers of nuclear power include deadly radioactive waste products.
核能效率高，不会产生含碳气体这样的废料。核能的风险包括致命的放射性废料。
A major source of energy comes from the burning of fossil fuels, such as coal and oil. When we burn fossil fuels, waste gases, such as CO2 are produced. Fossil fuels remain the largest source of energy for most countries.
能量主要来自于燃烧化石燃料，比如煤和石油。燃烧化石燃料时产生废气，比如CO2。化石燃料仍是大多数国家的最主要能量来源。
Hydropower comes from the kinetic energy of falling water. Output is reliable and can be regulated to meet the demand, except during periods of drought.
水力发电来自于水流的动能。产出可靠、可控以满足需要，除了枯水期间。
