They marched out singly or in pairs.

他们一个一个地或成双成对地走出去。

《柯林斯英汉双解大词典》

They always come in pairs.

他们总是成对地出现。

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These birds fly in pairs.

这些鸟成双成对地飞。

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The Smithsonian's National Museum of American History in Washington,D.C., has one of the oldest known pairs of Levi's jeans in its collection.

VOA: special.2009.12.18

And then it says, OK, distribute the remaining electrons in pairs so that each atom has eight.

然后它说，接下来将剩下的电子成对排布,使每个原子都有8个电子。

麻省理工公开课 - 固态化学导论课程节选

And even here at the law school, we wrote papers in pairs and as groups.

就算在法学院，我们也是成对和分组写论文的。

在模拟审判课堂 - SpeakingMax英语口语达人

Those tyrannised by the need, the obligation, to go about this world in pairs.

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Cars are lined up in pairs, bumper to bumper, coated with a week-old layer of dust.

NEWYORKER: Baptizing the Gun

This is reminiscent of their behaviour in conventional superconductors, where they wander around in pairs.

ECONOMIST: Magnetism