at的其他時間用法：
1.用在特定的時候（時節、時機）時,須用介詞at.例如：
They were happy at that time.他們那時很幸福.
I think the shop is clcsed at this time.我認為商店在白天的這個時候關門了.
2.表示“在中午、在夜晚、在周末”時,須用介詞at.例如：
What do you often do at noon?你中午經常做些什么?
You can see many stars in the sky at night.夜晚你能看到天空中有許多星星.
3.表示“在……歲”時,須用介詞at.例如：
At the age of nine ,the boy could swim
well.在九歲的時候,這孩子就游泳游得很好了.
At the age of twenty,I began to teach English at this school.在二十歲的時候,我就開始在這所學校教英語了.