Similarly, if it is dusty or there are a lot of other larger particles in the air, this will filter out larger wavelengths, resulting in a red sky and red sun.

同样，如果空气中尘埃比较多，或是空气中有很多其它大颗粒，那么那些较长的光波就会被过滤掉，于是天空就会是红色，太阳也会是红色。

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Behind them black clouds piled one atop another against a blood-red sky.

在他们身后是血红天空上的一团相互堆叠着的黑云。

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Red sky is a sign of good weather, but black clouds are a sign of rain.

红色的天空是好天气的征兆，而乌云则是下雨的征兆。

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Red sky is a sign of good weather, but black clouds are a sign of rain.

红色的天空是好天气的征兆，而乌云则是下雨的征兆。

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