英文科學(xué)讀本 第一冊(cè)·Lesson 21 The Sheep

Lesson 21 The Sheep

Come into the field, said Fred, "and let us watch the sheep feeding. But you must not go too near them, for they are very timid, and will run away."

Can you tell me why the sheep has that thick woolly coat, Norah?

I suppose it is because it always sleeps in the open air at night. The thick coat of wool is to keep it warm.

Quite right. Now let us sit down here, and watch the sheep eat the grass. You see they are all eating in the same way. They tear off one mouthful after another, and swallow it at once. They do not wait to chew it. They will not leave off till they have eaten as much as they want. Then they will lie down on the ground very quiet and still.

Some of them seem to have had enough already, said Norah, "for they are lying down over there. But they all look as if they were chewing now, Fred."

So they are, said Fred. "I will tell you all about it. First of all, then, I must tell you that the sheep has no teeth at all in the front of its top jaw. It has a thick, hard pad there instead of teeth. It collects the grass, a mouthful at a time, with its long tongue and lips. The sharp cutting teeth in front of the lower jaw press the grass against the pad and tear it off, and then the sheep swallows the whole of it just as it is."

The mouthfuls of grass pass down into a big bag, which we call the paunch. All the time the sheep is lying down, it is bringing up the grass into its mouth again to chew it. When it is chewed the sheep swallows it again, but it goes down now into another stomach.

We say the sheep chews the cud, for the grass is brought up in little balls or cuds to be chewed.

Look at the sheep's feet now, said Will. "They have four toes: two large ones in front, and two little ones behind. The sheep walks on the two front toes. Each toe has a hard horny case over it. We call the sheep's foot a hoof, and because it is split in two, we call it a cloven hoof."

SUMMARY

The sheep chews the cud. It has no teeth in the front of its top jaw; it has only a pad there. It has great teeth for chewing or grinding, and the jaw moves from side to side, as well as up and down. The sheep tears off and swallows each mouthful of grass without chewing it, then brings it all back into its mouth to be chewed, and at last swallows it again. The sheep has a cloven hoof. Its foot has four toes, but it walks only on the two front ones. It has a thick coat of wool.