at后面加什么时态

　　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。