介词用at，例如：
1、At midday everyone would go down to Reg's Cafe中午，大家都会下楼去雷吉餐馆。
2、I assure you that I shall be here at midday tomorrow.我向你保证明天中午我一定到这儿。
3、The train arrives at midday.列车正午到达。
4、But I know it's not like you to be in your cups at midday.但我知道你不会在大白天就喝酒。
