Today is an unforgettable day to me.

今天对我来说是一个难忘的日子。

Overall, we had an unforgettable day.

总的来说，我们度过了一个难忘的一天。

My whole family had an unforgettable day.

我们全家一起度过了难忘的一天。

An unforgettable day, it is worth remembering one day.

难忘的一天，值得记住的一天。

Last Mid-Autumn Festival was an unforgettable day for me.

对我来说，去年的中秋节是难忘的一天。