at后面加什么时间介词

用在特定的时候（时节、时机）时，须用介词at；

表示“某一具体时刻(即几点几分时)”,须用介词at

The weather is very changeable at this time of year.

年年在这个时候天气都变化无常。

Almost all homes have at least one TV set.

差不多每家都至少有一台电视机。

I was still in short trousers at the time.

我那时还在穿着短裤呢。

Both their children are at university.

他们的两个孩子都在上大学。

He met his future wife at law school.

他在法学院结识了他未来的妻子。