His bad behaviour was just an isolated incident.

他的不良行为只是个别事件。

《牛津词典》

Apparently the boy had a longstanding reputation for bad behaviour and his mum for even worse behaviour if he was challenged.

很显然，这个男孩恶行多端的臭名流传已久，他妈妈亦是如此，如果儿子受到质疑，妈妈的行为会更恶劣。

youdao

Three children were removed from the school for persistent bad behaviour.

三个孩子因持续行为不检被学校开除。

《牛津词典》

Their analysis showed that bad behaviour without psychopathy has relatively little genetic component less than a third.

ECONOMIST: Evidence that psychopaths are born, not made

In so doing, he neatly but unconvincingly removes the physical basis for good or bad behaviour.

ECONOMIST: Where there��s a will there��s a way

But a united front would change the environment that encourages the rogue state's bad behaviour.

ECONOMIST: Coping with North Korea: How do you solve a problem like Korea? | The