美国学生人类历史第5期:人类历史舞台的形成(2)（在线收听） |
Meanwhile the plants had increased in number and they had to search for new dwelling places. There was no more room for them at the bottom of the sea. 与此同时，植物的数量也在不断滋长，海底的空间已经不够容纳它们了。
Reluctantly they left the water and made a new home in the marshes and on the mudbanks that lay at the foot of the mountains.
为了生存，它们不得不开辟新的栖息地，很不情愿地在沼泽和山脚下的泥岸上安了新家。
Twice a day the tides of the ocean covered them with their brine.
每天早晚的潮汐淹没了它们，让它们品尝到故乡的咸味。
For the rest of the time, the plants made the best of their uncomfortable situation
除此之外的时间里，它们不得不学习如何适应不舒适的环境，
and tried to survive in the thin air which surrounded the surface of the planet.
争取在覆盖地球表面的稀薄空气里生存下来。
After centuries of training, they learned how to live as comfortably in the air as they had done in the water.
经过长时间的训练，它们终于学会了如何自在地生活于空气里，就像以前在水中一样。
They increased in size and became shrubs and trees
它们的体形逐渐增大，变成了灌水和树林。
and at last they learned how to grow lovely flowers which attracted the attention of the busy big bumble-bees and the birds
最后，它们还学会如何开出美丽的花朵，将忙碌的大黄蜂和鸟儿吸引过来，
who carried the seeds far and wide until the whole earth had become covered with green pastures, or lay dark under the shadow of the big trees.
并将它们的种子带到远方，使整个陆地都布满碧绿的原野和大树的浓荫。
But some of the fishes too had begun to leave the sea, and they had learned how to breathe with lungs as well as with gills.
此时一些鱼类也开始迁离海洋。它们学会既用鳃，也用肺呼吸。
We call such creatures amphibious, which means that they are able to live with equal ease on the land and in the water.
我们叫它们两栖动物，意思是，它们在水里和陆上都能活得同样悠游自在。
The first frog who crosses your path can tell you all about the pleasures of the double existence of the amphibian.
你在路边看见的第一只青蛙就能告诉你身为两栖动物穿梭于水陆之间的乐趣。
Once outside of the water, these animals gradually adapted themselves more and more to life on land.
一旦离开了水，这些动物会变得越来越适应陆上生活。
Some became reptiles (creatures who crawl like lizards) and they shared the silence of the forests with the insects.
其中的一些成为了爬行动物（那些像蜥蜴一样爬行的动物），他们与昆虫们一起分享森林的寂静。
That they might move faster through the soft soil,
为便于更迅速地穿过松软的土壤，
they improved upon their legs and their size increased until the world was populated with gigantic forms
它们逐渐发展自己的四肢，体形也相应地增大。最终，整个世界都被这些身高三十到四十英尺的庞然大物占领。
(which the handbooks of biology list under the names of Ichthyosaurus and Megalosaurus and Brontosaurus)
这些庞然大物就是被生物学手册称为鱼龙、斑龙、雷龙等等的恐龙家族。
who grew to be thirty to forty feet long and who could have played with elephants as a full grown cat plays with her kittens.
若它们跟大象 玩耍，就如同体形壮硕的成年猫逗弄自己的小惠子。
Some of the members of this reptilian family began to live in the tops of the trees, which were then often more than a hundred feet high.
后来，这些爬行动物家族中的一些成员开始到上百英尺高的树顶会生活。
They no longer needed their legs for the purpose of walking, but it was necessary for them to move quickly from branch to branch.
它们不必再用腿来走路，可迅速地从一棵 树枝跃到另一棵树枝，却变成了树上生活的必需技能。
And so they changed a part of their skin into a sort of parachute, which stretched between the sides of their bodies and the small toes of their fore-feet,
于是，它们身体两侧和脚趾间的部分皮肤逐渐变成一种类似降落伞的肉膜，
and gradually they covered this skinny parachute with feathers and made their tails into a steering gear and flew from tree to tree and developed into true birds.
这些薄薄的肉膜上又长出了羽毛， 尾巴则成为了方向航。就这样，它们开始在树林间飞行，最终进化成真正的鸟类。 |
| 原文地址：http://www.tingroom.com/lesson/mgxsrls/375095.html |