Regular repeating actions such as sound waves, light waves, or radio waves have a certain frequency, or number of waves per second.

有规律的重复活动如声波、光波、无线电波都有一个特定的频率，或者说是每秒的波动次数。

《柯林斯英汉双解大词典》

Another belief involving the number three has it that it is unlucky to light three cigarettes from the one match.

另一种与数字3有关的信仰认为，用一根火柴点燃三根香烟是不吉利的。

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For a number of other galaxies, astronomers can circumvent the dark-matter problem by observing how a galaxy bends the light of more distant galaxies.

对于一些别的星系，天文学家可以通过观测星系怎样扭曲更远的星系发出的光来规避暗物质的问题。

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Does it need refinement in some way?" "And if it does need some adjustment in light of the events that have taken place over the last number of months, including the election and so on, and then what are the implications of that in terms of General McChrystal's resource request?" The secretary said the United States will not abandon its core mission in Afghanistan, which President Obama described as the destruction of the al-Qaida terrorist network, because it is "critical" to U.S.national security.

VOA: standard.2009.10.23

So this gives you a little bit of an idea of just how many individual photons there are in a laser beam of light. This is a huge number of photons.

这个给你们一点思路关于,一个激光束有多少独立的光子,这是一个巨大的光子数目。

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The others in the direct light sending the same number of photos to your eye.

那些直接处于光线之下的瓷片,向你的眼睛发出了同样多的图片。

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The team also showed how a large number of light pipes could be used to form a kind of dot matrix display.

BBC: Disney develops 3D-printed lighting for toys

The board have ruled that Oakey's first defence must be against Brian Magee, the number one light heavyweight contender from Belfast, before the end of October.

BBC: Dominant Oakey crushes Spartacus

Patricia Hughes had many outside interests, including gardening, animals and the piano and she also wrote a number of light music pieces that the record producer Joe Meek helped her to have published - including one, It Happened in a Dream, which reportedly still earns royalties today.

BBC: Patricia Hughes