They are shaped like little chisels.
它们的形状就像凿子一样。
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.
这些切牙的边沿总是如凿子一般锋利, 因为每颗牙齿的前端都是由一种名叫釉质的物质构成, 非常坚硬, 而牙齿的其他各部分则较软。所以, 相对前半部分来说, 牙齿的后半部分磨损更快。于是, 每颗牙齿就总是能够保持尖锐、锋利的状态。我们的钢制凿子同样采用了这种设计结构:刀口由坚硬的薄钢片制成, 后面再附上一块更厚的软铁。
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.
利用这些锋利的切牙, 老鼠能够轻松地在木板上打洞。老鼠嘴巴的后部则长有磨牙, 可以将食物磨成碎片。老鼠以谷物及各类种子为食。它们经常窜到农场的谷仓里偷吃谷物, 造成巨大的破坏。
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.
你有没有看到过老鼠嘴巴两侧那长长的“胡须”? 它们就像是触角一样, 当老鼠在地下或房间中的木头夹层或壁板内那些阴暗、狭窄的过道中穿梭时, 就可以通过它们来探查周围的情况。
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.
你有没有在笼子中饲养过家鼠呢? 每只小白鼠大概需要四个便士。如果你已经开始饲养家鼠, 一定要好好照顾它们。给它们一点面包和牛奶或者粥, 再添加一些橡子和坚果。必须保证它们所居住的笼子非常干净。家鼠很快就会认识你, 听到呼唤, 它们立刻就会跑上来爬上你的胳膊。