They bear traces of red ochre, a pigment.

这些外壳上有赭红色颜料着色的痕迹。

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Passionate visitors came in an endless stream to look for traces of the Red Crag heroes.

热心的的参观者们排着长队来这里寻找红岩英雄们的踪迹。

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The bright red bowl, or arc, seen in this image traces the outer surface of the dense dust cloud encasing the young stars.

图中可见红色的弧形，它是一层致密气体的外层表面，这层气体则遮盖着那些年轻的恒星。

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These beads even bore traces of red ochre, used as a pigment.

BBC: NEWS | Science/Nature | Study reveals 'oldest jewellery'

They said the temple walls were made of stone and covered in fine yellow clay which also contained some traces of red paint.

BBC: El Paraiso site

The reaction to this debacle was so strong that manufacturers not only scrambled to remove any last traces of Red 2 from products but also stopped using other permitted red colorings.

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