在中午用in还是on

在中午用at。

noon，正午，所指的时间范围很小，可以看成是某个时刻，所以用at，同样用at还有midnight，午夜。

at noon adv.在中午

He decided to cook the fish at noon.

他决定在中午做鱼。

The festival parade will begin at noon.

节日*行将在中午开始。

At noon, you can go to the Summer Palace.

中午，你可以去颐和园。

At noon, everyone was glad to have a picnic lunch.

中午，每个人都很高兴有一个野餐午餐。

One day, when the Lion was asleep at noon, the little Mouse came running by.

一天，当狮子在中午睡觉的时候，小老鼠跑了过来。

If someone invites you to meet him or her at noon, then you're expected to be there at noon.