请假：ask for leave (of absence)
请假一节课：ask for a class hour's leave (of absence)
请一节课的病假：ask for a class hour's sick leave (of absence)
请一节课的事假：ask for a class hour's business leave (of absence) 请假：ask for leave (of absence)
请假一节课：ask for a class hour's leave (of absence)
请一节课的病假：ask for a class hour's sick leave (of absence)
请一节课的事假：ask for a class hour's business leave (of absence)