与美国小学生一起学英文第12册 第5期:渗透作用(在线收听

   Osmosis 渗透作用

  When you water plants or flowers, do you pour water on their leaves? 你给植物或花浇水时,会把水倒在它们的叶子上吗?
  No, you don't. You may pour water on the ground. 不,你不会。你可能把水倒在地上
  Then the plants and flowers absorb water through their roots. 然后植物和花从根部吸收水分。
  How can they do so? 它们怎么办到的呢》
  It is because they can perform osmosis. 这是因为它们可以进行渗透作用。
  Osmosis is the phenomenon of water flow. 渗透作用是水流动的现象。
  The roots of plants work as a filter. 植物的根是一个过滤器。
  They prohibit the nutrients in the roots from going out of the plants, but let the water in the plants. 它们禁止根部的营养成分流出去,但又让水分进来。
  Plants usually have big and long roots, because they want to absorb more water from the ground. 植物的根通常大而长,因为它们想从地面吸收更多的水分。
  原文地址:http://www.tingroom.com/lesson/ymgxxsyqxyy/d12c/429615.html