1. Birds are creatures which fly.
    鸟是会飞的动物。

2. Birds learn to fly by instinct.
    鸟会飞是出自本能.

3. Birds have the power to fly.
    鸟能飞。

4. We owe a lot to the birds and beasts who eat insects.
    我们十分感激食虫的飞禽和走兽.

5. We eat the flesh of animals , birds , and fish.
    我们吃兽类、禽类和鱼类的肉。

6. We owe a lot to the birds and beasts who eat insects but all of them put together kill only a fraction of the number destroyed by spiders.
    我们要十分感谢那些吃昆虫的鸟和兽，然而把它们所杀死的昆虫全部加在一起也只相当于蜘蛛所消灭的一小部分。

7. When you think of the innumerable birds that one sees flying about,
    你可以想象出天上有看得见的飞来飞去、数不清的鸟，

8. When the blood of the languishing birds was examined, it was found teeming with malaria parasites.
    把这些快要死去的麻雀的血取出来检验，血液中充满了疟疾寄生虫。

9. The valleys echoed the chirping of the birds.
    吱吱喳喳的鸟鸣在谷中回响。

10. The birds have flown away.
    鸟儿都飞走了。