in + 今天中的上午下午晚上：in the morning/afternoon/evening;
in the day(在白天）
in + 月、年 in June; in 2011;
in + 一段时间：表示过……
in ten days 过十天
on + 某天：On Sunday; on June 1st;
在某天的上午下午晚上：on the morning/afternoon/evening of June 1st
on Sunday morning