开心的名词用英文怎么说

看他好像吃了一惊，她感到开心。

She had the pleasure of seeing him look surprised.

知道有人欣赏我所做的.事真让人开心。

It's nice to know that somebody appreciates what I do.

孩子们追逐着彼此的影子，玩得很开心。

The children were having fun, chasing each other's shadows.

我没有察觉到你那么不开心。

I didn't realize you were so unhappy.

我没有察觉到原来他那时非常不开心。

I didn't realize but he was deeply unhappy at that time.