9．现在，打开那个冲洗过面粉的棉布包。里面还有什么剩余物质吗？有，我们可以看到少量黄白色的粘稠物质。这种东西的正式名称就是面筋④。由此我们就可以说，面粉中包括淀粉与小麦蛋白。不过，这其中还有一些水分以及小麦的根部从土壤中吸收到的极少量碳酸盐。
10．面粉有什么用处呢？孩子们都知道，面粉可以用来制作面包、布丁与糕点。在制作面包时，需要在面粉中加入一些水、酵母以及少量盐分。我们用手和面，将这些食材均匀混合在一起，就成为了结实而很有弹性的生面团。
11．然后，我们将生面团放在温热的地方大约二十分钟，让它能够膨胀或者“发起来”。随后，将面团切割成块，每一块都是一块面包的尺寸，然后将它们放入烤箱中烘烤两个小时左右。
12．你有没有注意过，面包烤得好，就能呈现非常明显的海绵状结构？这是因为酵母在面团内部生成了一种名叫碳酸气⑤的气体。烤箱中的热量将气体排出面包之外，于是，面包中便形成了气孔或气道。
13．酵母是一种非常有趣的物质。实际上，它是一簇植物群；然而，每种植物都太过微小，借助显微镜才能看到。这些植物在面团中迅速生长，在这个过程中，它们会生成很多碳酸气。面团之所以能够发起来，原因就在于此。
14．吃面包有什么好处呢？小麦淀粉能够形成你的肌肉，碳酸盐可以加固你的骨骼，而淀粉则带来了身体所需的热量与体能。因此，面包是一种很好的食物，因为它几乎包含我们身体所需的各类营养⑥。
译注
①关于小麦的结构和成长，请参见第22课注释。
②关于这个“打谷”或者“打麦”的过程，请参见第34课注释。那里说的是大麦的脱粒，但小麦脱粒的过程也是类似的。
③这个说法，自然是老皇历了。我河北的老家，在60年代末也淘汰了石磨。现在磨面用的是电动磨面机，只有一些非常小的家用石磨用来磨豆浆。
④现代科学中，面筋的学名叫“谷蛋白”（amorphous protein）。
⑤碳酸气是俗称，学名是我们很熟悉的二氧化碳（carbon dioxide）。
⑥关于馒头和面包的区别，请参见第22课注释。
THE BODY
人体
1.This lesson is going to be about our own selves-about our bodies.Every one wants to have a nice-looking and healthy body，which will live a long time.So we ought to learn about our bodies，in order that we may know how to take care of them.
2.The body，as we can easily see，consists of a large central part or trunk，which has on the top of it a round ball，called the head.To the four corners of the trunk are attached①the limbs.
The limbs are in two pairs-an upper pair，called the arms，and a lower pair，called the legs.
3.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.This skin contains many thousands of tiny holes called pores，out of which sweat or perspiration is always coming.To keep these pores open，we must wash our skin often and well.If we allow the pores to be always closed up with dirt and sweat，we shall soon begin to feel ill.
4.The nails on our fingers and toes are only parts of the skinwhich have grown very hard.The teeth，also，are very hard pieces①Attached，joined.
of the skin of our gums，although they look more like bone than skin；and even the hairs of our head are only pieces of the skin which have grown very long and thread-like.
5.Have you ever counted your teeth？A very young baby has no teeth which you can see，for its teeth are hidden inside its gums.They begin to grow through the soft gums，and the first teeth peepout like little pearls①when baby isa few months old.By the time the child is two years old，it has got its first complete set of teeth.These are called “milk-teeth；”they are twenty in number，ten being in the upper jaw and ten in the lower.
6.In a few years more the milk-teeth begin to go.Another set of teeth，called the permanent teeth，is growing，one under each of the milk-teeth，and pushing out the first set.Some new teeth also grow behind the milk-teeth at each side of the mouth.The new teeth are thirty-two in number，there being sixteen in each jaw.The tooth farthest back at each side of each jaw is the last to grow.You will not have these four back teeth until you are about twenty-one years of age，and so these teeth are called your “wisdom-teeth.”
7.Permanent means “lasting，”and these second or permanent teeth ought to last you all the rest of your life.But to make them last，you must take care of them by brushing them at least twice every day with a toothbrush.Be sure to use your teeth well in chewing your food；for if you swallow your food half chewed-or “bolt”it，as people say-you will be sure to be ill and to suffer pain.
①Pearls，small，white，and shining gems，found in some shell-fish.
8.Can you feel under your skin the lumps of firm red flesh which are called muscles？Feel the strong muscle in your upper arm，and notice how it becomes harder and shorter and thickeras your lower arm is raised，and how it relaxes①as the arm is straightened again.In thewhole of your body there are about four hundred such muscles.
9.Underneath the muscles you can feel something harder still-your bones.There are about two hundred separate bones in your body.The ends of many of these bones are joined together by strong bands.All the bones taken together form what is called the skeleton②.
10.The ends of some of the muscles are fastened to the bones by strong cords or strings called sinews.As the muscles contract③，they move the bones which are fastened to them；and this is the way in which our legs are made to move when we are walking，and our hands when we are working.
SUMMARY
The body consists of the head，the trunk，and the limbs.The outside of the body is entirely covered by the skin，which varies in thickness，and contains a great number of small pores，through which the perspiration passes.The nails，teeth，and hair have all grown from the skin.A child’s first set of teeth is called the milk-teeth.They are twenty in number.In a few years these teeth are replaced by thirty-two permanent teeth.The teeth should be well used in chewing food.Under the skin are the muscles，of which there are about four①Relaxes，slackens.
②Skeleton，framework；the bones of an animal without skin or flesh.
③Contract，draw together.
hundred in the body.Underneath the muscles are the bones，which number about two hundred.The muscles are fastened to the bones by sinews.
【中文阅读】
1．这篇文章讲述的是我们自己--人体①。谁都希望自己拥有漂亮、健康的身体，这样就能够延年益寿。因此我们应该了解自己的身体，从而明白如何照顾好自己。
2．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。躯干四个角落的位置上长有我们的四肢②。四肢分为两对：上面的一对称为胳膊，下面的一对则是腿。
3．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③。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。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。如果任由毛孔被污垢与汗水堵塞，我们很快就会生病。
4．我们的手指与脚趾上的指甲④，只是长得非常坚硬的一部分皮肤而已。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；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。
5．你有没有数过自己一共有多少颗牙齿？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。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。幼儿发育到两岁时，就拥有了人生第一套完整的牙齿。这些就是“乳牙”⑤：共有二十颗，上下腭各有十颗。