小梅把家里的小电风扇从插座上拔下，如图所示，将小灯泡与电风扇插头的两金属片相连接，用手快速拨动风扇叶片，发现灯泡发光，电风扇发电的原理是____ ，发电过程是把____ 能转化为电能．

如图，AB是⊙O的直径，BC是⊙O的弦．若∠OBC=60°，则∠BAC的度数是（　　）

如图，AB//CD，∠CDE=140$°$，则∠A的度数为（   ）

—She goes to America ________.

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                                                                                                                                  春山夜月
                                                                                                                                  唐·于良史
                                                                                                                 春山多胜事，赏玩夜忘归。
                                                                                                                 掬水月在手，弄花香满衣。
                                                                                                                 兴来无远近，欲去惜芳菲。
                                                                                                                 南望鸣钟处，楼台深翠微。