英语时差：风力发电机

If you’ve ever driven by a wind farm, you may have noticed that the turbines most likely have three blades. Not two, not five, but three. Now, you may think that if the point of a wind turbine is to capture wind, wouldn’t five blades capture more wind than three? And wouldn’t capturing more wind translate to generating more electricity? Why? The answer depends on what’s meant by capturing wind. The goal of an electricity generating turbine isn’t exactly to capture the most wind possible. It’s to capture wind with the greatest efficiency. And engineers have found that three blades is the most efficient and least troublesome way to harvest wind.