Vitamin D helps our bodies make a special chemical, and this special chemical, ______, affects our brains, making us feel happy.[ ]

A. in turn  

B. in particular

C. in advance  

D. in short

如图所示，风力发电有利于推动________（透填“可再生”或“不可再生”）能源的开发利用和生态环境的保护．华中地区首座风电场--湖北通山九宫山风电场的开工建设，既为神奇秀美的九宫山增添一道靓丽的风景，又促进了咸宁市能源结构的改变．工作时的能量转化是：风车将带动发电机．发电机将________能转化为________能．发电机是跟据________现象制成的．