书城教材教辅科学读本(英文原版)(套装1-6册)
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第214章 第三册(39)

"Geese and swans of course belong to the same class of birds.""The nut-cracking birds have very curious beaks," saidWillie. "Next time you see a parrot, Norah, have a good look at its beak. It is a short, strong, hooked bill, with a sharp point.

"These birds and others of the same class live on nuts, fruits, and berries, and they use their strong bills as their nutcrackers.""Most of our small birds live on seeds, don"t they?" asked Norah.

"Yes, and we might put them all in one class and call them seed-eating birds," said Fred.

"The beak is short, hard, and strong,

and shaped like a cone. They use these bills to crack the husks of the seeds.""Oh yes," said Norah, " I have often watched our canary crack his seeds and drop the husks on the floor of the cage."SUMMARY

Ducks, geese, and swans have flat, shovel-like bills. They grope in the mud with them for grubs and worms. The nut- cracking birds have hard, strong, hooked bills. The beaks of the seed-eating birds are short and cone-shaped.

Lesson 13

Vapor-What Becomes of It