They are happy cuz they won the game.

他们很高兴因为他们赢了比赛。

They are happy coz they won the game.

他们很高兴因为他们赢了比赛。

Babies often vocalize when they are happy.

婴儿在高兴时常常会发声。

Her family is very poor, but they are happy.

她的家庭非常贫穷，但他们很快乐。

In the sentence They are happy, are functions as a copula.

在句子“他们很高兴”中，“是”起系动词的作用。

They went through a lot, but after a storm comes a calm, they are happy now.

他们经历了很多，但雨过天晴，现在他们很幸福。

He showed how crows call when they are happy and cheerful.

他展示了乌鸦在快乐和欢快的时候是如何叫的。

Yes. They are happy with us.

是的，他们与我们住在一起很开心。

The lion and the mouse are happy.They are friends.

这狮子和这老鼠是快乐的。它们是朋友。

They remember their history. They are happy to be Americans.

他们纪念自己的历史， 以身为美国人为乐。