at night泛指在夜晚，中间不用冠词。是与in the day（白天）相对照的短语。

At night，families often stay in the open air near their house.

晚上，家家户户常常呆在离家不远的外面。

Ever since then，the bat comes out only at night.

从那时起，蝙蝠只在夜里出来。

in the night指某个夜晚，不具体，相当于during the night，night前有定冠词。

In the northeast，there will be snow in the night.

东北地区晚上将会下雪。

She come back at eleven in the night.

他在夜里十一点钟回来了。

on the night指一个特定的夜晚。表示特定的方法有两种：1.在night后面有of短语加以限制；2.night前有修饰语。

The story happed on the night of October 25，1980.

故事发生在1980年10月25日深夜。

You’d better not go out on such a cold wet night.

在这样寒冷潮湿的夜晚，你最好不要出去。

自我测试

根据句意，用at night，in the night或on the night填空。

    1.We work in the day-time and sleep ______ .

    2.I saw him ______ of May 1st，1999.

    3.He came back at about eleven o’clock ______.

答 案: 1.at night  2.on the night  3.in the night