base layer

基本解释

As the electric crawler inches forward along a sand base layer, the bricks are automatically packed together by gravity.
随着这个电动铺路者在砂基路面上一点点向前行进，砖块便因为地心引力自动码放在一起。
Often, you will only need this in the coldest weather, when the fleece adds extra insulation between your base layer and your outer layer.
通常你只在最冷的日子才需要穿上这一层衣物，羊毛会在你的内衣和外套之间建立一个额外的隔绝层。
Leaving it out can cause problems such as being unable to pan at all or having additional layers badly misaligned on top of the base layer.
如果不指定，可能会出问题，比如根本不能平移或是有额外的层在基层上不能很好地对齐。

The base layer of modern skis is made from a substance called ultra-high-molecular-weight polyethylene.
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Dual-shot adds a second layer of colored, transparent or translucent polycarbonate on top of a base layer to produce secondary color blends and depth effects.
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a piece of clothing worn under your other clothes, made of material that is designed to keep you warm and dry