They became the first April fools.

他们就成为第一批“四月愚人”。

Today is April Fools 'day.

今天是愚人节。

It's a April Fools' joke.

这是个愚人节的玩笑。

She smiled to us and said "April fools"!

她微笑着对我们说：“愚人节快乐”！

Dad: Do you know about April Fools' day?

爸爸：你知道愚人节吗？