【英语时差8,16】修剪皮肤

At some time we've all probably taken a long bath, or been in the pool for awhile, and then noticed that parts of the palms of our hands and the bottoms of our feet become wrinkled.   This Moment of Science answers two questions about this: why does it happen, and why doesn't our whole body wrinkle like that?

The answer lies in the structure of our skin, and that it's not the same all over. The outer layer of skin, the epidermis¹, on our palms and the soles of our feet is thicker than the skin on the rest of our body. When we soak in water the epidermis all over our body absorbs some water and swells³. Because the skin on our palms and soles is thicker it can absorb more water, and therefore swells more.

That seems simple enough, but why do the ends of our fingers and toes wrinkle up like prunes⁵ and not the rest of us? Most of our skin absorbs water and swells rather evenly, but there is something different about the ends of our toes and fingers: there is a nail on one side. The ends of the fingers and toes can't swell² toward the nails, so the skin bunches up opposite the nails on the palm side of our fingers, and the sole side of our toes. This bunching up of the skin gives us the wrinkles -- prune⁴ skin.  

1 epidermis   

n.表皮

参考例句：

• The external layer of skin is called the epidermis.皮的外层叫表皮。
• There is a neoplasm originating in his leg's epidermis.他的腿上有个生长在表皮上的肿瘤。

2 swell   

vi.膨胀，肿胀；增长，增强

参考例句：

• The waves had taken on a deep swell.海浪汹涌。
• His injured wrist began to swell.他那受伤的手腕开始肿了。

3 swells   

增强( swell的第三人称单数 )； 肿胀； （使）凸出； 充满（激情）

参考例句：

• The waters were heaving up in great swells. 河水正在急剧上升。
• A barrel swells in the middle. 水桶中部隆起。

4 prune   

n.酶干；vt.修剪，砍掉，削减；vi.删除

参考例句：

• Will you prune away the unnecessary adjectives in the passage?把这段文字中不必要的形容词删去好吗？
• It is our job to prune the side branches of these trees.我们的工作就是修剪这些树的侧枝。

5 prunes   

n.西梅脯，西梅干( prune的名词复数 )v.修剪（树木等）( prune的第三人称单数 )；精简某事物，除去某事物多余的部分

参考例句：

• Dried fruits such as prunes, pears, and peaches, are stewed. 梅干、梨脯、桃脯等干果，都是炖过的。 来自辞典例句
• We had stewed prunes for breakfast. 我们早饭吃炖梅干。 来自辞典例句