Man has    1 four kinds of satellites. The first kind of satellites studies the   2    of the earth. They are used to make maps. They also help countries to see    3   they can find oil or gold.

    The second kind of satellites is used to guide   4   and planes. A ship or a plane can        5    a message to the satellite, and the satellite can find out where it is. The third kind of satellites studies the  6    . These satellites watch clouds and strong winds   7   across the earth. They warn countries to make preparations when very   8 weather is coming. They take photos of the earth from miles above it and send the photos to weather   9   on the ground.   The last kind is used for    10  .Telephone calls 11 countries can be sent by these satellites. Some can carry hundreds of 12   at one time. The call is sent to the satellite and then the satellite send it to the station in the country  13  is being phoned. These satellites also carry    14 , they can send about eight programs  15   .

    People like dolphins because they are both lovely and clever. They have an 1 IQ (智商).

Dolphins can 'talk'. Scientists try to ‘talk' with dolphins, and the results make them 2. They find that dolphins 3 understand them so well.

4 animals enjoy playing, but dolphins like to make their games different. On a beautiful day in 1997, scientists on a beach 5 a little dog going into the sea. They were surprised to see the dolphins come up to the dog and then start throwing(扔) it into the air. The dog 6 the 'game' and kept playing with the dolphins for over an hour.

    Dolphins live in a very different world from 7, but they are very good at our 'IQ tests(测试)'. For example, in the picture above, a dolphin jumps 8 the water when he hears a whistle noise(哨声). He does this because he will get a fish 9 an award.

    There is 10 much to learn about these lovely friends.

    National Eye Care Day on June 6th is a good chance for us to improve our eye health. What are common eye problems we have today? How can we protect our eyes? Read on to find out the answer.

    Eyes are important in our everyday life. We use them to read books, see colors and view the wonders of the world. But sometimes, we use them too much and it hurts them.

    In the past , nearsightedness（近视）was a common eye problem among children . This is mostly because of their bad eye habits, such as watching TV too long and reading books in bed .

    However , today's technology is changing the way we live . Children spend more time working and playing in front of computers , smart phones and iPads . US children spend more than 42 hours a week in front of electronic screens（电子屏幕）, US'ABC news reported .

    This has caused a new problem for our eyes : digital（数字的）eyestrain（眼疲劳）. People with digital eyestrain may get headaches , dry and red eyes , eye pain , watering and other eye problems .But don't worry . The following tips can help you protect your eyes . Try them out .

Screen advice :

⒈ When you are watching electronic screens , keep them at least 30 cm from your eyes . Try not to use your smart phone in direct sunlight .

⒉ Blink（眨眼）more often when you are looking at the screen . This can help to stop dry eyes .

⒊ Remember to take a 20-20-20 break : every 20 minutes , take a 20second break and look at something 20 feet ( about 6 meters ) away .

⒋ Spend less time in front of screens . One to two hours a day is OK for your eyes .

    A grown-up person has ten or eleven pints(品脱) of blood inside his or her body. We can lose a pint of blood without feeling anything, but if we lose too much blood, we feel weak and cold. Our faces become pale(苍白). We may die. This is what often1when somebody is hurt in an accident or a soldier is hurt in a battle. Many people used to die in this way. But nowadays they can be taken to the hospital. If they are given more blood at once, they will feel better. Their faces are no longer pale. They do not die.

    Where does this blood come from? People who are2give some blood so that it can be used in this way. Every three months they go to a place where blood is collected. A special kind of needle is put into the arm. It does not hurt. The blood runs3the needle and a rubber tube into a bottle. A pint of blood is taken in this way. Then the person who has given the blood drinks a cup of tea or coffee. He sits down for a few minutes. Then he feels quite well and goes off. Three months4he comes back and gives another pint.

    A person who gives blood5feels happy. He knows that his blood will be used to save someone's life. Perhaps one day he himself will need blood.

    When you grow older, you may decide to give blood in this way. But you cannot do this6you are eighteen.