Who hasn't enjoyed eating peanuts? Did you know that although peanuts look like nuts and taste like nuts, they aren't nuts at all? They belong to the pea family, so they are called peanuts. The peanut grows flowers above ground, but its "fruit" grows underground. It grows in more countries than most other "nuts”.
   The peanut is a native South American plant. Scientists believe that it grew wild in Brazil long ago. They think that for several thousand years the early peoples of South America made it a part of their diet. These peoples were nomads who moved on when a natural food could no longer be found in one area. Along the way they probably let fall some peanuts, which got into the ground and grew. This is believed to be the way the plant reached the place where the Incas（印加人）lived. The Incas, from about 1100 to 1532, thought highly of peanuts. The peanuts were eaten in several forms and used as sacrificial offerings（祭品）to the Incan Sun God. Later in the 16^th century, European soldiers had brought peanuts to other parts of the world, including North America, Africa, Asia, Europe, and Pacific Islands.
   Although peanuts were found native in South America, they are now grown in almost every country that has warm weather. India produces the most peanuts. China's production is next, followed by the United States.
   The peanut is special in more ways than one. It can be eaten raw, boiled, roasted, or fried. Hundreds of widely different products have been made from it. Carver, an American scientist, set himself the task of discovering new uses for eating and for many other products.
  Peanuts are very highly nutritious and are also high in protein （蛋白质）. Americans use about seven-tenths of their protein in the form of meat. In India, where the poor can't pay for meat or milk, peanut meal and peanut milk have been produced. These have been a great help to the poor.
  New products are continually being made from peanuts, among them peanut cheese and a powder that becomes peanut butter when water is added. The fact is that peanuts are so healthy that they were used by astronauts. The unusual nut that isn't a nut is one of nature’s most amazing gifts.

一个物体沿着南北方向在运动，若规定向南记作正，向北记作负，则该物体：

原地不动记作____米

    You probably know many of the things that you can do with the hundreds of different muscles in your body. But have you ever thought about how the muscles in an animal's body are different from yours? An animal's muscles are made to do the things that are most important for its life.

    Lions are hunters. They depend on their ability to catch other animals. Lions must be fast in order to catch their prey(猎物). The powerful muscles in their back legs allow them to run at speeds of more than 30 miles per hour. They can also jump a distance of more than 35 feet. The strong muscles in their front legs help them catch their prey.

    Snakes also use their muscles for hunting prey and for movement, but their muscles work in very different ways than lions' do. Because snakes do not have any legs, they use their muscles to push against the ground or other objects to move themselves forward. Their muscles also allow them to eat things that seem much too large. For example, a snake may eat an egg that is larger than the width of its body. How does this happen? The snake's strong neck muscles work together to push the egg down the mouth.

    The elephant's long nose has a lot of muscles. Scientists believe that the nose alone has more than 100,000 muscles! This is because the elephant uses its nose much in the same way that people use their hands and fingers. Even though the nose is large, it can perform surprisingly tasks. For example, an elephant can pick up a small leaf from the ground. The nose can also be a powerful tool. An elephant can use its nose to pick up a tree by its roots or even to lift a baby elephant.

    The great muscles of these animals seem pretty unbelievable. But the muscles in your body work exactly the way you need them to. After all, it might be fun to be able to jump a distance of 30 feet, but as a human being, there is just not much need for it.