他为了自保，最终向警方告发了他的同伙。

He ended up ___ratting out his partners to the police to save himself.

农夫训练他的狗擅长在谷仓里捕鼠。

The farmer trained his dog to be good at ___ratting in the barn.

如果你再迟到，我就不得不开始记录你翘课的情况了。

If you're late again, I'll have to start ___reporting on your skipping classes.