Often, you will only need this in the coldest weather, when the fleece adds extra insulation between your base layer and your outer layer.

通常你只会在最冷的天气才需要这个，羊毛会在你的底层和外套之间增加一个额外的隔绝层。

Glass can be used as the outer layer.

外层可以使用玻璃。

Top this with a waterproof, breathable outer layer.

在这一层之上，是防水透气的外层。

The cortex is the outer layer and the outer layer is all crumpled up.

大脑皮层是大脑的外层，上面布满了褶皱。

Their purpose is to remove the damaged outer layer of your skin.

它们的目的是消除损害外层你的皮肤。