Biofuels have been around for a long time and they are the least expensive renewable energy source.
生物燃料已经被使用了很长时间，并且它也是最便宜的可再生能源。
Wind power has emerged as a viable renewable energy source in recent years - one that proponents say could lessen the threat of global warming.
风能是近几年呼声最高的可再生资源——其中一个原因在于，支持者们认为风能可以降低全球变暖的威胁。
Recent years, wind power as a kind of clean and renewable energy source is drawing more and more attention.
近年来，风能作为一种清洁环保而储量丰富的可再生资源，日益成为各国研究的热点。
At present, wind power is the most mature renewable energy source in technology and can be explored in large-scale development.
风力发电作为目前技术最成熟与最具规模开发的新能源，日益受到关注和重视。
How does the shape of wind turbine blades affect the performance of this kind of renewable energy source?
叶片形状对用于风力发电的风力涡轮机的发电性能的影响？
How does the shape of wind turbine blades affect the performance of this kind of renewable energy source?
叶片形状对用于风力发电的风力涡轮机的发电性能的影响？
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