A smile passed fleetingly across his face.

笑容从他的脸上一闪即逝。

《柯林斯英汉双解大词典》

She was only their temporary custodian, she said, a form and a face caught fleetingly by the movie camera or posing, in soft focus, behind the hard stones.

她说，她只是他们的临时监护人，被电影摄像机迅速捕捉、在硬石头后面柔焦的聚光灯下摆姿势的一个人罢了。

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He enrolled fleetingly in high schools in London and Sarajevo, Yugoslavia, but rarely attended.

他曾短暂的在伦敦及南斯拉夫萨拉热窝入高中上学，但很少上课。

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He mentioned Simpson-Bowles fleetingly in his State of the Union speech a month later.

WSJ: Fred Barnes: Obama and the Back-to-the-Future Campaign

Perhaps pity was a truer description of what I felt for him, however fleetingly.

NPR: Sergeant Notes Odd Rituals of War in Afghanistan

What does it say about us that these disgraced politicians have success -- however fleetingly -- after their scandals?

CNN: Zombie politicians find new life after disgrace