He vowed to himself to avenge his martyred comrade.

他暗暗发誓要为牺牲的同志报仇。

《新英汉大辞典》

He vowed to take legal action.

他发誓要诉诸法律行动。

《柯林斯英汉双解大词典》

He vowed (that) he had not hurt her.

他起誓他没有伤害过她。

《牛津词典》

When Irish voters approved the treaty earlier this month in a second referendum, he vowed to keep his word.

VOA: standard.2009.10.10

You remember that Milton had vowed to his friend Charles Diodati in the Sixth Elegy that he would become an epic poet some day, and that he was taking all of the necessary steps to transform himself into an epic poet.

弥尔顿曾在第六挽歌中向他的朋友查尔斯，迪奥达蒂宣布,他有一天将成为一名史诗诗人，他也在不断努力,把自己变为一名史诗诗人。

耶鲁公开课 - 弥尔顿课程节选

To the cheers of his supporters, he vowed to build more jails to imprison his political opponents who he says are corrupt.

VOA: standard.2009.07.19

And he vowed to act on climate change himself if Congress failed to enact legislation.

BBC: State of the Union: Obama pledges to reignite economy

He vowed to examine every part of the company, especially areas that weren't generating profits.

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" He vowed that Pakistan constitution would be restored saying, quote, "There would be no dictatorship.

NPR: White House Wants Pakistan Elections