My heart was pounding fit to burst.

我的心跳得非常厉害，简直要炸了。

Harry was watching his aunt, utterly bewildered, his head throbbing fit to burst.

哈利无比惊愕地望着姨妈，脑袋疼得像要裂开一般。

The girls were laughing fit to burst.

【fit】女孩子们笑破了肚皮。

There are birds singing in the bushes and the pond is full of frogs, croaking fit to burst.

草丛中有鸟儿在歌唱，池塘里满是青蛙，呱呱叫。