手指泡水久了，为什么会起皱？

Stay in the bath too long, and your fingers wrinkle. 洗澡泡久了，手指就皱巴巴的。 Scientists used to think water soaked in. 科学家以前以为，是水渗进了皮肤。 Now they know the blood under the skin shrinks. 现在才知道，是皮下的血液缩了水。 The skin is pulled in, and small lines show. 皮肤被往里一拉，就起了小皱。 Scientists think the wrinkles help you grip. 科学家认为，这些小皱帮你抓得更稳。 They help your hands hold wet things tight. 它们帮你的手，抓紧湿滑的东西。 Next bath, look at your funny prune fingers. 下回洗澡，看看自己的葡萄干小手。