For Mona Lisa, he used a thin-grained piece of poplar tree and applied an undercoat of lead, white.

在创作《莎》时，他使用了一棵纹理很薄的白杨树，并涂了一白色的铅底漆。

It consists of two layers of transparent hair, a soft thick undercoat and a layer of hollow guard hairs.

它有透明皮毛，一是柔软厚实的皮毛，一是中空的护毛。

He then applied a series of undercoats, letting them dry before applying another.

然后，他涂了一系列的底漆，等它们干了再涂一。

But for many mammals, hair grows in two layers consisting of a shorter undercoat of ground hairs covered by longer guard hairs.

许多哺乳动物的毛发生长为，较短的毛作为底毛发，上面覆盖较长的保护毛。

The lead white undercoat reflects the light back through his glazes, giving the picture more depth, and in essence, lighting Mona Lisa from within.

铅白色的底漆将光线通过釉料反射回来，使这幅画更有深度，从内部照亮了《莎》。

Woolly mammoth fur was composed of two coats: an inch-long yellowish brown undercoat that was covered by a coarse dark brown overcoat that could grow more than two feet long.

长毛猛犸象的皮毛有：一英寸长的黄褐色下皮毛，上面覆盖着一粗糙的深棕色外毛，可以长到英尺多长。