He lost his train of thought for a moment, then recovered it.

他一时断了思路，接着又重新想起来了。

《柯林斯英汉双解大词典》

He had a nasty moment when he thought he'd lost his passport.

他以为护照丢了，苦恼极了。

《牛津词典》

He paused, apparently lost in thought.

他停顿下来，显然陷入了沉思。

《牛津词典》

Helen looked straight up at the sky as if a lost memory or thought of some kind was coming back to her.

VOA: special.2009.11.08

My parents thought I'd lost my mind to drop out of Stanford Business School to go join some company that made software.

我父母认为我从斯坦福商学院,辍学去一家软件公司工作根本是疯了。

斯坦福公开课 - 微软CEO-Steve.Ballmer谈科技的未来课程节选

I always got lost, so I thought what better way to do then,

我经常迷路，所以我思考有什么更好的方法，

伦敦的出租车司机 - SpeakingMax英语口语达人

At the gym I did my dumb struts on the elliptical and lapsed into spells of lost thought.

NEWYORKER: Midnight in Dostoevsky

As the junior allies, British officers felt they could do nothing in Basra to change the course of a war being lost, they thought, by American troops in Baghdad.

ECONOMIST: Britain's armed forces

"There is certainly more interest now and support for speaking Zapotec, " adding that the revival of the Zapatec language is happening in places where it had been thought lost.

BBC: Oaxaca festival in Mexico highlights indigenous pride