It is one of the happiest days of the year.

这是全年最快乐的日子之一。

This is the happiest day of my life.

这是我一生中最快乐的一天。

He is the happiest person in the world.

他是世界上最幸福的人。

Childhood is the happiest time of my life.

童年是我最快乐的时光。

She looks the happiest when she is painting.

她画画时看起来是最快乐的。

She is the happiest when she is with her family.

她和家人在一起时是最快乐的。

He feels the happiest when he is playing his guitar.

他弹吉他时感到最快乐的。

The children were the happiest during the summer vacation.

孩子们在暑假期间是最快乐的。

Learning to ride a bike was one of the happiest moments of my childhood.

学会骑车是我童年最开心的事之一。

He is the happiest man alive.

他是世界上最快乐的人.