in the morning (一段时间,如上午,中午,晚上,夜晚,用in;点时间用at;如1:5,天用on,如在一月一日,周一;月份, 如在一月,年,如在一年 用in。)
in the morning/afternoon/evening at nighton 要有特定的日期 比如 on Sunday morning/afternoon/evening/night
in the morning
in the morningin the afternoonat night