VOA慢速英语:Everyday Grammar: In, On, and At

短语讲解：

1. Moving to shorter, more specific periods of time, we use on to talk about particular days, dates, and holidays .

talk about 讨论，谈论
例句：He went on to talk about his accident.
他接着谈到了他的意外事故。

2. When English speakers refer to a place, we use in for the largest or most general places.

refer to 涉及; 指的是
例句：Don' t refer to that problem again, please.
请不要再提那个问题了。