<拉>饭前(服)
In Europe, AC is usually generated at 50 Hz.
欧洲的交流电输出频率通常为50赫兹。
The Prime Minister ac-cused opposition leaders of muck-raking.
首相指控反对党领袖传播丑闻。
Both ac-tivities have caused some ructions.
两项活动都引起了一些抗议。