他看了一眼她戴的帽子，突然大笑起来。

He took one look at the hat she was wearing and ___burst ___out laughing.

我突然哭了起来，因为我的围裙完全烧焦了。

I ___burst ___out crying because my apron had burned completely.

当歌手出现在舞台上时，观众突然大喊起来。

The audience ___burst ___out shouting when the singer appeared on stage.