为了开开心

in order to cheer up

玩得很开心

play happily

人民大众开心之日，就是反动派难受之时。

The day the masses are happy is the day that reactionary factions squirm in pain.

孩子们玩新玩具很开心。

The children played happily with the new toys.

弄得大家都不开心

ended up with nobody being happy

你为什么这么不开心？

Why are you so unhappy?

他们想拿我开心。

They want to make fun of me.

她爱拿别人开心。

She likes making fun of others.