Over millions of years ago, there were deserts. Now about one fifth of the Earth's surface {#blank#}1{#/blank#}(be) deserts. The size of the world's deserts is always {#blank#}2{#/blank#}(change). Deserts can be hot or cold. The Australian Desert is a hot desert, while the Gobi Desert in Mongolia is an example of a cold desert. Deserts are dry areas {#blank#}3{#/blank#}less than 50 cm of rain falls each year. The Sahara Desert in Africa receives less than 1.5 cm a year.

      {#blank#}4{#/blank#} rain doesn't fall very often in deserts, sometimes even for years, there can be heavy rain

{#blank#}5{#/blank#}(sudden). Because they are dry,deserts have wide changes in temperature each day. When the sun{#blank#}6{#/blank#}(go) up, it is very hot. At night, the heat {#blank#}7{#/blank#}(receive) by the ground during the day {#blank#}8{#/blank#}(quick) disappears(消失), and then it becomes very cold. Because {#blank#}9{#/blank#}the change, living in the desert is very difficult. Man can make deserts, but they can also stop them from getting larger and larger. Planting trees can prevent the sand from{#blank#}10{#/blank#}(spread).

    The computer is increasingly popular in people's{#blank#}1{#/blank#}(day) life. The number of computers in every family is{#blank#}2{#/blank#}(much) than TV sets. Some people think the computer is so great that they all regard it as a gift{#blank#}3{#/blank#}the heaven. However, some people consider it brings more disadvantages than advantages.{#blank#}4{#/blank#}my opinion, both opinions are correct, but if we can use the computer in a proper way, its advantages are superior to disadvantages. I have several reasons.

    The computer makes human beings' life become{#blank#}5{#/blank#}(easy). People can do many things that they couldn't do before. They can read newspapers {#blank#}6{#/blank#}(with) buying them, only sitting in front of the computer, clicking the mouse to open websites. Shopping online, watching films,{#blank#}7{#/blank#}(listen) music and playing computer games are the common things that people often do on the computer. But without computers, they can't do all these easily. In addition, computers{#blank#}8{#/blank#}also very helpful for study and work. People can have classes and work on them.

    In general, the computer has advantages and disadvantages. But if people can control{#blank#}9{#/blank#}(them) to use the computer properly, it is{#blank#}10{#/blank#}(use) for their whole life.