英國學(xué)生科學(xué)讀本 Lesson 76 家鼠(2)
它們的形狀就像鑿子一樣。
These cutting teeth always keep their sharp, chisel-like edge, for the front of each tooth is formed of a very hard stuff called enamel, while the rest of the tooth is made of softer material. So the back part of each tooth wears away faster than the front part, and thus the teeth are always kept pointed and sharp. Our best steel chisels are made on the same plan: at the cutting edge they have a thin plate of hard steel, which is supported or backed up by a thicker plate of softer steel.
這些切牙的邊沿總是如鑿子一般鋒利, 因為每顆牙齒的前端都是由一種名叫釉質(zhì)的物質(zhì)構(gòu)成, 非常堅硬, 而牙齒的其他各部分則較軟。所以, 相對前半部分來說, 牙齒的后半部分磨損更快。于是, 每顆牙齒就總是能夠保持尖銳、鋒利的狀態(tài)。我們的鋼制鑿子同樣采用了這種設(shè)計結(jié)構(gòu)：刀口由堅硬的薄鋼片制成, 后面再附上一塊更厚的軟鐵。
With these sharp gnawing teeth mice can soon cut their way through wooden boards. At the back of the mouth there are grinding teeth, which crush the animal's food into small pieces. Mice feed on grain, and on all kinds of seeds. They often do much damage by eating the corn in the farmer's wheat-stacks.
利用這些鋒利的切牙, 老鼠能夠輕松地在木板上打洞。老鼠嘴巴的后部則長有磨牙, 可以將食物磨成碎片。老鼠以谷物及各類種子為食。它們經(jīng)常竄到農(nóng)場的谷倉里偷吃谷物, 造成巨大的破壞。
Do you see the long "whiskers" of the mouse, which stick out from each side of its mouth? These act as feelers, and let the mouse know if there is anything in its way, when it is running along the dark, narrow passages under the floors or behind the wooden lining or wainscot of our rooms.
你有沒有看到過老鼠嘴巴兩側(cè)那長長的“胡須”? 它們就像是觸角一樣, 當老鼠在地下或房間中的木頭夾層或壁板內(nèi)那些陰暗、狹窄的過道中穿梭時, 就可以通過它們來探查周圍的情況。
Did you ever keep tame mice in a cage? You can buy white mice for about fourpence each. If you get any, you must look after them well. Give them a little bread and milk or porridge to eat, with some acorns and nuts. You must keep their cages very clean. Tame mice will soon learn to know you, and will come to you and run up your arm when you call them.
你有沒有在籠子中飼養(yǎng)過家鼠呢? 每只小白鼠大概需要四個便士。如果你已經(jīng)開始飼養(yǎng)家鼠, 一定要好好照顧它們。給它們一點面包和牛奶或者粥, 再添加一些橡子和堅果。必須保證它們所居住的籠子非常干凈。家鼠很快就會認識你, 聽到呼喚, 它們立刻就會跑上來爬上你的胳膊。
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