at表示时间的一点;in表示一个时期;on表示特殊日子。
at后常接几点几分,天明,中午,日出,日落,开始等。
in后常接年,月,日期,上午,下午,晚上,白天,季节,世纪等。
on后常接某日,星期几,某日或某周日的朝夕,节日等。
望采纳
根据定语从句中介词与先行词的搭配关系选择,如:
I will never forget the day on which I came to this school. (on the day)故用介词on
I still remember the days during which we were young. (during the days)故用during