夏日的風可以帶來涼意，冬日的風可以吹起漫天的雪花，此外，風還有什么作用呢？
The production tax credit for renewable forms of energy was supposed to end this December. But Congress has extended it through 2008. Other reasons for the expansion include improved turbine technology and lower production costs. They also include policies that make it easier for wind power producer…