Hardly fastidious homemakers, the birds raise their nestlings in the dark on a layer of tiny fish bones regurgitated as pellets, then shattered with a perfunctory peck.

而亲鸟是几乎不会挑剔的主妇，它们会堆砌起细小的鱼骨头，然后很随意的捣碎这些堆砌物，在这层层鱼骨头形成的阴影里喂养嗷嗷待哺的小鸟。

youdao

A layer of low clouds creates the dark red line along the lower part of the profile.

一层低空云层在剖面图的下方形成了深红色的线。

youdao

They are transient tangles in the sun’s magnetic field that are slightly cooler than their surroundings and so appear as dark patches in the photosphere—the surface layer of the sun.

它们是位于太阳磁场上暂时性的比周边温度偏低的混乱的一块区域，也因此看起来就像光球——太阳表层上的暗斑。

youdao

C. and A.D. 500 by brushing away the dark top layer of barren desert to reveal the light, sandy soil underneath, wrote Clive Ruggles, an archaeologist from the University of Leicester in the United Kingdom, in an email.

MSN: Peru's mysterious Nazca Lines form a labyrinth, says study

But further measurements using a laser and looking for reflections showed that much of the ice is covered with a layer of dark material tens of centimetres thick.

BBC: Mercury's water ice at north pole finally proven

The blue layer of sky had given way now and was turning dark like the rest.

NEWYORKER: Beginners