This Lesson is going to be about our own selves—about our bodies. 这篇文章讲述的是我们自己——人体。

　　Every one wants to have a nice-looking and healthy body, which will live a long time. 谁都希望自己拥有漂亮、健康的身体, 这样就能够延年益寿。

　　So we ought to learn about our bodies, in order that we may know how to take care of them. 因此我们应该了解自己的身体, 从而明白如何照顾好自己。

　　The body, as we can easily see, consists of a large round central part or trunk, which has on the top of it a round ball, called the head. 我们可以很轻松地观察到自己身体的外部结构：一个很大的中心部分或者说是躯干, 这上面是一个圆球, 也就是脑袋。

　　To the four corners of the trunk are attached the limbs. 躯干四个角落的位置上长有我们的四肢。

　　The limbs are in two pairs—an upper pair, called the arms, and a lower pair, called the legs. 四肢分为两对：上面的一对称为胳膊, 下面的一对则是腿。

　　The outside of the body is entirely covered by the skin, which varies from one-eighth of an inch to one quarter of an inch in thickness. 我们的身体表面全部都被皮肤所包裹, 其厚度从八分之一英寸到四分之一英寸不等。

　　This skin contains many thousands of tiny holes called pores, out of which sweat or perspiration is always coming. 皮肤上长有成千上万的小孔, 这就是毛孔, 汗水就是通过这里流出体外。

　　To keep these pores open, we must wash our skin often and well. 为了确保这些毛孔畅通, 我们必须经常洗澡, 并且要认真清洗。

　　If we allow the pores to be always closed up with dirt and sweat, we shall soon begin to feel ill. 如果任由毛孔被污垢与汗水堵塞, 我们很快就会生病。

　　The nails on our fingers and toes are only parts of the skin which have grown very hard. 我们的手指与脚趾上的指甲, 只是长得非常坚硬的一部分皮肤而已。

　　The teeth, also, are very hard pieces of the skin of our gums, although they look more like bone than skin; 同样的, 虽然看起来更像是骨头, 但牙齿实际上也是牙龈上的皮肤；

　　and even the hairs of our head are only pieces of the skin which have grown very long and thread-like. 除此之外, 我们的头发也是皮肤的一部分, 它们只是发育成了细长的样子而已。

　　Have you ever counted your teeth? 你有没有数过自己一共有多少颗牙齿?

　　A very young baby has no teeth which you can see, for its teeth are hidden inside its gums. 你肯定看到过, 新生婴儿没有牙齿, 或者说他们的牙齿埋藏在牙龈下方。

　　They begin to grow through the soft gums, and the first teeth peep out like little pearls when baby is a few months old. 当婴儿长到几个月时, 牙齿就会从柔软的牙龈中生长而出, 看起来就像是珍珠一样。

　　By the time the child is two years old, it has got its first complete set of teeth. 幼儿发育到两岁时, 就拥有了人生第一套完整的牙齿。

　　These are called "milk-teeth;" they are twenty in number, ten being in the upper jaw and ten in the lower. 这些就是“乳牙”：共有二十颗, 上下腭各有十颗。