at the beginning of可以指时间，也可以指位置。指时间时（着重于一点）意为“在……之初”，指位置时意为“在……开头”。

This happened at the beginning of the year.

这件事发生在年初。

This word can’t be used at the beginning of the sentence.

这个词不能用于句子的开头。

in the beginning仅指时间（着重于时间段），意为“起初、在初期”，相当于at first，其后不能接of短语，常用作状语。

In the beginning she was not interested in swimming，but now she has become a good swimmer.

起初她对游泳不感兴趣，可现在却成为一名游泳好手。

He didn’t like it in the beginning.

开始，他不喜欢它。

自我测试

请将下列句子译成英语。

    1.一

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.