at后加什么词

at属于介词，介词后面都是接名词的，像时间名词，地点名词。at的用法主要有动词+at，at表示“指向某一目标，到达某地”；be+形容词/过去分词+at，at表示“情绪、情感的原因，或对某物具有某种感情”；at+名词构成的词组等。

Children begin to go to school at the age of seven.

孩子们7岁开始上学。

After a long walk they arrived at a farmhouse at last.

经过长途跋涉，他们终于到了一家农舍。

The school bus will be ready at the gate at eight tomorrow.

明天8点在校门口有校车等候。

The two countries were at war then.

那时两个国家正在交战。

We were sad at hearing such bad news.

我们为听到这样的坏消息而悲伤。