阅读理解

Find Which Direction Is South

    Do you have a good sense of direction? If not, please take with you a compass. But if you forget to take a compass, you can still find your way. 

    It's never a wise idea to believe that the family member who was good at the job of map-reading knows where the family is. You can tell by the troubled look on their faces that nothing on the ground seems to match the map. Never mind. The sun is shining and it's still morning. If you don't know the exact time, you can still find out where south is, but you'll need to be patient. 

    ①Find a straight stick and put it in the ground in a place where you can mark its shadow(a dark shape on a surface that is made when something stands between a light and the surface). 

    ②Try to position the stick as vertically(垂直)as you can. You can check this by making a simple plumb line(铅锤线). You haven't got one? OK, use a thread(线) from your clothes with a button(纽扣) tied at the end to act as a weight.

    ③Mark the end of the shadow cast(投射) by the stick.

    ④Wait about half an hour and mark the end of the shadow again.

    ⑤Keep doing this until you have made several marks. 

    ⑥The mark nearest the stick will represent the shortest shadow, which is cast at midday, when the sun is highest in the sky and pointing to the exact south. 

    ⑦Pick a point in the distance along the line between the shortest shadow and the stick.

    ⑧That point is south of where you are. 

    ⑨Now you can turn the map, like you did before, and find which way you should be travelling. 

    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.

    The tiger is the largest wild cat in the world. It is the king of animals. Tigers often eat 5kg of meat for a meal. Tigers can see very well in the dark. They often hunt at night. Sometimes they can eat 27kg of meat at one night. Most members of the cat family dislike water, but tigers enjoy water. They are good at swimming. Many animals live in groups, but tigers live alone（单独地）, except for（除了） mothers and their young babies. A mother tiger usually has two or three babies at one time. She takes care of them by herself.

    There were eight kinds of tigers in the world, but three of them died out（灭绝）. There are only about 3200wild tigers in the world now because people kill tigers and destroy the places where they live.

    A long time ago, people thought that the Sun went round the Earth. In some countries people even said that the Sun was a god (神). They thought the god drove across the sky each day on a golden horse. Now we know the Earth goes round the Sun. It takes the Earth a year to go all way round the Sun. Today men even know how far it is for the Earth to go round the Sun. They tell us that the Earth travels over a thousand miles a minute on its journey round the Sun.

    The Sun is really a star. It is much bigger than the Earth and it is very hot. Some people have been to the Moon but we know that no one can ever go to the Sun. It is far too hot for people to live anywhere near it. The Sun is about three hundred thousand times heavier than the Earth and more than a million times larger.