他输了比赛后，朋友们对着他唱起了‘啦啦啦’来开玩笑。

After he lost the game, his friends sang '___na-na-na' at him playfully.

这首歌的副歌部分全是'啦啦啦'，没有实际歌词。

The song's chorus consists entirely of '___na-na-na' without any real lyrics.

“这道题太简单了，na-na-na！”她得意地说道。

"___Na-na-na, this is so easy!" she said proudly.