What insects have one pair of wings? What insects have two pairs of wings?

什么昆虫有一对翅膀，什么昆虫有二对翅膀？

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If there are three different faces, there is either two pair or three of a kind.

如果有三张不同的牌面，则有两对或三张相同的牌。

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That’s more than one or even two pair of shoes ladies. This is obviously not HIS idea of romance!

不止是一两双鞋,女士们.这显然不是他的浪漫想法!

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The global reach of the Marley tribute CD includes a pair of Canadian vocalists, two groups from Hawaii, and the veteran string band from the northeastern U.S.

VOA: standard.2010.07.22

A covalent bond is any time we have a pair of electrons that is shared between two different atoms.

所谓共价键就是我们有两个原子,共用一对电子。

麻省理工公开课 - 化学原理课程节选

So in oxygen we have a similar situation where, in fact, we are not going to promote any of the electrons because we have two lone pair electrons no matter what we do.

在氧中，情况很类似，我们不能激发电子,因为无论如何我们都有两个孤对电子。

麻省理工公开课 - 化学原理课程节选

My most precious asset surely was two pair of dry woolen socks, snug in my field jacket pockets.

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There are nine cameras hard-mounted to the rover: two pairs of black-and-white Hazard Avoidance Cameras in the front, another two pair mounted to the rear of the rover, (dashed arrows in the graphic) and the color Mars Descent Imager (MARDI).

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Buying Take-Two would pair one of the videogaming industry's steadiest performers with an inspired, if turbulent, hit factory.

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