There is little doubt that house cat first developed naturally from ancient wild cats. The cleverest relative is the America wild cat which still lives in Africa today. This is understandable because the first house cats came from Africa.

    Cats first started to live around people in Egypt about 6,000~7,000 years ago. From Egypt, cats started to move around the world. This is about the same time that Egyptians began storing grain(谷物）in buildings. Scientists used to believe that people tamed cats to catch mice and protect the grain. However, cats don't like to be told what to do! Now, scientists believed that cats followed the mice and learned to accept people. Finally, some of the cats began to grow comfortable around people, these were smaller cats that needed protection. As these cats and people got used to each other, then they moved in together. Around 5,000 years ago, cats started to live with people.

   Soon cats were in Greece, then the Middle East and China. They moved along Egyptian business roads keeping away mice and keeping people around them. After the Romans came to Egypt, they also accepted the cats and brought them to Europe. These cat likely bred(繁殖） with other cats to form the many kinds of house cats we have today.

    Cats are relatively recent house animals. House cats still have a lot in common with their wild relatives. Cats sleep a lot to save energy just like wild cats. They will often get food at night as well. House cats are generally peaceful and friendly, but be careful! If a cat feels it is in danger, it will fight back—just like a wild cat.

    Are you able to send a letter with pictures and sounds to someone somewhere in the world without a stamp(邮票) on it? Using a computer you can send e-mails quickly and easily. The post is much slower than e-mail. E-mail can send its message to the other side of the world in seconds.

    E-mail is easy to use and it saves time and money. The differences in time in different parts of the world do not matter when sending e-mail. It's twenty-four-hour service(服务) that you can send e-mail at any time of the day or night. No one has to be there to get e-mail. It does not matter if your friends are in beds when you send e-mail to them, or you are seeing a movie at the movie theater when they send e-mail back.

    How much sleep do we need? We are all different. Some people need only three hours of sleep a night. Others need ten hours of sleep a night. Most Americans sleep an average(平均) of seven to eight hours a night. After the age of fifty, the average sleeping time goes down to 6.5 hours a night.

    Most people have a bad night when they cannot fall asleep(睡着). The name of this problem is called insomnia.

    This isn't a new problem .Many famous people in history had insomnia .Some of these people had special ideas to make them sleep .Benjamin Franklin, the famous inventor had four beds. He moved from one to another to fall asleep .King Louis XIV(国王路易十四)of France had four hundred and thirteen beds and hoped to fall asleep in one of them .Mark Twain, the famous American writer, had a different way. He lay on his side across the end of his bed.

    Stop reading for a minute and think about what you see when you look up at the sky on a clear night. You probably see many stars(星星). Long long ago, farmers watch some stars to know when to plant their crops. Travellers did so to find their way in the dark. Today stars are still important to some people.

    Scientists find that most stars are very big. In fact some stars are so far away that it would take millions of years to get to them even by spaceship.

    Another thing we know today about stars is that some are made up of(由……组成) hot gases. The gases are so hot that they send out light. If you watch a star carefully, you may notice that it twinkles(闪烁) sometimes. As you may understand, light from a star must shine through the air before you can see the star. Air is always moving, it makes light from the star move back and forth. When the light moves, it makes the star twinkle. Stars also have different colours. The colours of a star depend on how hot it is. To our surprise, the cool stars are red and the hottest stars are white.