如果需要拍照,请关闭闪光灯
Should you need to take photos,please turn off the flashlight.
拍照时请关闭闪光灯
Please turn off the flashlight when taking photos.
上课时请将手机设为静音
Please set your mobile phones mute（或silient）in class.
再问： 上课时请将手机设为静音 怎么翻译比较客气一点
再答： Could you please cooperate to set your mobile phones mute（或silient）in class? 你们能配合上课时将手机设为静音？