He broke off in the middle of a sentence.

他一句话说了一半就不说了。

《牛津词典》

He broke off the paint on the car.

他把汽车上的油漆弄掉了。

youdao

He broke off his engagement to her.

他和她解除了婚约。

《新英汉大辞典》

Defenseman Ryan McDonagh chopped his stick down across the crossbar with such force that he broke off the blade.

WSJ: Mixed Emotions for Rangers as Season Ends

Lori Drew, 49, allegedly posed as a boy on the website to befriend Megan Meier, 13, who hanged herself after he broke off the virtual relationship.

BBC: Myspace website

Then he broke off and grinned.

NEWYORKER: Beginners