There is little rain in desert. Because deserts are so dry, they have no "quilt" to help stop the soil from going away. As a result, they may get very hot during the day with the sun shining, but don't hold the heat overnight. Many deserts can quickly get cold once the sun goes down. Some deserts can reach temperatures of over 100 degrees F during the day and then drop below freezing (32 degrees F) during the night.

The largest hot and dry desert in the world is the Sahara Desert in Northern Africa. The Sahara is a sandy desert with great sand hills. It covers over 3 million square miles of Africa. Other large deserts include the Arabian Desert in the Middle East, the Gobi Desert in Northern China and Mongolia, and Kalahari Desert in Africa.

Animals that live in the desert are also used to needing little water. Many get all the water they need from the food they eat. Other animals keep water that they can use later. The camel stores up fat in its hump while other animals keep something they need in their tails.

Only certain types of plants can live in the terrible environment of the desert. You won't see a lot of tall trees in the desert. Most plants have a way to keep water in their leaves, or trunks so they can live a long time without water.

Now deserts cover around 20% of the world's land, but they are growing. This is called desertification and is caused by different reasons including human activities. The Sahara Desert is growing larger and larger each year. What should we do with it ?

    Since the beginning of history, man has been fascinated by the idea of living forever, of winning the fight against death and disease. So far, this has only remained a dream, though a very powerful one. Many people have wondered whether it would be possible to find a way to preserve human bodies, and what would be the best way to preserve human bodies.

    It has long been known that meat or fruit can be kept fresh for long periods by freezing; in ancient China, for example, food was stored with ice to keep it fresh. This method could also be useful for preserving humans, and in fact many people have explored this possibility.

    However, most living beings that exist under warm conditions die when frozen. This is because of the harmful effects of freezing ice crystals, which are not only larger than the volume of the water originally in the cells, but also form sharp cutting shapes that harm the cells.

    In the 1940s Dr B. J. Luyet and a group of scientists in England were working on the problem of freezing cells without damaging them. Since the harm caused by ice crystals was the main cause of the damage, Luyet suggested removing some or all of the water from the cells before freezing them.

    Using living cells from chicken, Luyet and his assistants discovered that they could partly dry the chicken cells, using a mixture of the white part of an egg and glycerin, a clear thick liquid made chiefly from fats and oils. Some success was obtained. The chicken cells were dried, frozen for a period of time, and then carefully unfrozen.

    Almost all the cells recovered when they reached normal temperature. Since then, the cooling of whole animals to a temperature very much below freezing point for later unfreezing has become more of a possibility, and the glycerin method would probably be used to accomplish this. When this can be done completely and successfully, science will have moved much closer to its aim of freezing and storing incurable patients until the day they can be cured.

Everyone needs friends. We all like to feel close to someone. 1 is nice to have a friend to talk to, and to do things with. 2 , sometimes we need to be alone. We don't always want people 3 us. But we will feel lonely if we never have a friend.

No two people are just the same. Friends 4 don't get on well. It doesn't mean that they no longer 5 each other. Most of the time they will make up（言归于好） and become friends again. Sometimes friends move away. Then we feel very 6 . We miss them very much, but we can 7 them and write to them. And we can make new friends. It is surprising to find out 8 we like new people when we get to know them.

There is more good 9 for people who have friends. They live longer than people who don't have any friends. Why? It could be true that they are 10 . Being happy helps you stay well. Or it could be just knowing that someone cares. If someone cares about you, you will take better care of yourself.

When we think of Hollywood（好莱坞），we think of films and famous （著名的）film stars.{#blank#}1{#/blank#}Today people make films in other places，too.Not all famous film stars live in Hollywood.{#blank#}2{#/blank#}You can easily see where Hollywood is in Los Angeles（洛杉矶）. {#blank#}3{#/blank#} It says "HOLIYWOOD".The white letters are fifty feet tall.You can see the sign from far away.The Hollywood sign is a famous Hollywood landmark（印迹） Los Angeles.Many postcards show this famous Hollywood landmark.

In the hill（小山）of Hollywood，there is also the Hollywood Bowl.{#blank#}4{#/blank#} It has seventeen thousand seats and a very different stage（舞台）.{#blank#}5{#/blank#} You can listen to all kinds of concerts（音乐）at the Hollywood Bowl.

A．We all like the city.

B．There is a big sign（标志）on the hills.

C．Hollywood is a famous city in the USA．

D．They're part（部分）of Hollywood's history.

E．This is one of the open—air theaters（剧场）in the world.

F．The design（设计）of the stage was by a great American called Frank Lcoyed Wright.

G．But Hollywood is still a very special city in Los Angeles，California（加利福尼亚洲）.

 What happens if you swallow gum(吞口香糖) by accident? You might have heard that gum stays in your stomach for up to seven years. But is that true? Beth Czerwony, a doctor at Cleveland Clinic, will explain what really happens when a piece of gum makes its way into your stomach.

Is it bad to swallow gum?

 Swallowing one piece of gum every now and then isn't likely to do any harm. But you shouldn't make a habit of swallowing gum, as that can do some damage.

 Gum base is largely synthetic(人工合成的). It's nondigestible which means your body can't break it down like it does other foods." So it just stays in your stomach all the way through," Czerwony explains.

Does gum stay in your stomach for seven years?

 Don't worry: Gum doesn't stay in your stomach for seven years or even seven days.

" If you' ve swallowed a piece of gum, it' ll come out about 40 hours later in your stool(粪便)," Czerwony says." Because it can't be digested, it comes right out whole."

When should you go to your doctor?

 Swallowing one piece of gum probably won't hurt you, but beyond that, be careful. Dr. Czerwony warns that too much at a time can cause an intestinal blockage(肠道阻塞)." Anything you eat after that isn't going to be able to get through, which leads to pain and pressure." she says.

As young students, you have many dreams. These dreams can be very big, such as winning the Nobel Prize. They can also be small. You may just want to become one of the ten best students in you class. Once you find a dream, what do you do with it? Do you ever try to make your dream come true?

Andrew Matthews, an Australian writer, tells us that making our dreams real is life's biggest challenge. You may think you're not very good at some school subjects, or it is impossible for you to become a writer. These kinds of ideas stop you from realizing your dreams.

In fact, everyone can make his dream come true. The first thing you must do is to remember what your dream is. Don't let it leave your heart. Keep telling yourself what you want every day and your dream will come true faster. You should know that a big dream is, in fact, many small dreams.

Also you must never give up your dream. There will be barriers on the way to your dreams. Don't be afraid of them. They are not so hard. The biggest difficulty comes from yourself. You need to decide what is the most important. Turn off the TV. Studying will help you get better exam grades. Don't buy ice-cream. Saving five yuan means you can buy a new book.

As you get closer to your dream, it may change a little. This is good as you have the chance to learn something more useful and find new hobbies.