He knew in his inmost heart that he was behaving badly.

他内心深处知道他表现得很差。

《柯林斯英汉双解大词典》

Behaving badly yesterday, I am ashamed of myself now.

我昨天表现不好，现在我为自己感到羞愧。

youdao

Behaving badly or angrily, name calling and going on about things being "unfair" won't change the final result and will only make you look like a bad sport.

表现差、发脾气、谩骂以及抱怨“不公”不会改变最终结果，只会让你看起来像个糟糕的运动员。

youdao

I prepared a meal for my children but they were behaving badly.

VOA: special.2009.05.03

Then the circuits get packed too close, and you get a case of electrons behaving badly.

FORBES: BET ON THE HARES

Such a quibble aside, it is undeniable that "Models Behaving Badly" itself performs splendidly.

WSJ: Book Review: Models Behaving Badly

Responses to stories of Chinese behaving badly while traveling are mixed among China's online community, she says.

CNN: Chinese tourism: The good, the bad and the backlash