at night?in the night?

1.at night 表示泛指的“在夜晚”.at night 是固定搭配.night 前不加冠词,也没有其它修饰语,后面也不接短语或其它成份.eg
1) Bats go out to look for food at night.
蝙蝠夜间出去觅食.
2) He often stays up at night.他晚上经常熬夜.2.in the night 表示某个夜晚,不具体；后面不接其它修饰语,night 前用定冠词the,不用其它的修饰词.侧重于表示一个时间段,相当于during the night.eg
3) Jack called me three times in the night.
杰克在夜里给我打了三次电话.
4) He came to me at 8:30 in the night.
他那天晚上8:30到我这儿来的.
3.on the/a night 表示某一具体日期的夜晚,其后常跟of+具体日子或在night 前用其它的限定词来修饰.eg
5) The story happened on a cold winter night.
这个故事发生在寒冷的夜晚.
6) We saw the play on the first night.
第一天晚上我们就看了那场戏.
7) They arrived there on the late night of May 1st,1985.
他们在1985年5月1日深夜到达那儿.