用例子总是会很直观,请看：
我出生在纽约.I was born in New York.(born + in + 出身地)
我出生在1984年.I was born in 1984.(born + in + 年份)
我出生在1984年9月.I was born in 1984,Sept.(born + in + 年月)
我出生在1984年9月9日.I was born on Sept.9th,1984.
(born + on+ 年月日)
我出生在一个雨天.I was born on a rainy day.(born + on+ 特殊日子）
在具体的日期或时间要用ON.