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    6．Plants need CO2 when they grow, so they can make CO2 in the air. 【查看更多】

     

    题目列表(包括答案和解析)


    【小题1】_____________ (luck), he found his lost key in the reading room.
    【小题2】It is reported that they ___________ (donate) 20 million yuan to China Red Cross since last year.
    【小题3】The TV play My Ugly Mother is well worth ______________ (see) again.
    【小题4】My sister said that the capital of China ____________( be) Beijing .
    【小题5】It’s much____________(excite) to surf the Internet for teenagers.
    【小题6】They have done what they can_________ us stop the sandstorm. (help)
    【小题7】Plants need CO2 when they grow , so they can make CO2_______________(little) in the air.
    【小题8】Do you know the two ____________ (thief) names?
    【小题9】Green can make you feel _______________ ( energy ).
    【小题10】Zhang Jike shouted with _____________ (excite) when he got the first prize in the World Table Tennis Championships（锦标赛） several days ago.

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    用单词的适当形式填空。
    1. My aunt _____ (teach) me to play the violin when I was a child.
    2. Look! The people in the river ______ (swim).
    3. Tree-planting Day is on the ______ (twelve) of March every year.
    4. Stephen spends about half an hour ______ (swim) every Saturday afternoon.
    5. I don't like travelling by train. I think it's ______ (safe) to travel by train.
    6. —I'm tired. 
        —So am I. We'd better stop ______ (walk) and have a rest.
    7.  Plants need CO2 when they grow, so they can make CO2 ______ (little) in the air.

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    综合填空。
         用方框中所给词的适当形式填空，使短文正确、通顺。每词限用一次。
    go  grow  sell  protect  improve  another  animal  please  clean  lucky
         Have you ever noticed how cool it is to be under trees? Besides the   1   they give, trees can make our life
    better in other ways, too. Because trees need CO2 when they   2   , they can make CO2 less in the air. Also,
    trees can give off O2.
         Trees and forests play an important part in helping   3   our environment. They can stop the soil from being washed away or blown away. They can make water better. And they can make the air   4   . At the same time,
    forests are the home of many   5   .
         However, forests in our country and all ore7 the world are becoming fewer and fewer. People cut down
    trees to make paper or   6   them for money and do other things. For example, between 50 and 100 acres (英
    亩) of rainforests are destroyed every minute, if this   7   on, there will be no rainforests left in one hundred
    years. 
           8   , many countries come to know the importance of forests. They ask their people to   9   the forests
    and not to cut down trees too often. If people cut down one tree, they should plant  10   tree or more trees.
         How about you? Do you want to plant trees for your future? Are you ready? Let's go!

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    Air is all around us.It is around us as we talk and play, From the moment we were born , we are surrounded(围绕) by air. When we sit down ,air is also around us ,we live in air .

    All living things need air:living things cann’t live without air.

    We can go without food or water for a few days ,but we can not live for more than a few minutes without air. When we are working or running ,we need some air. So we breathe faster than usual. When we are asleep, we need less air.

    1.From the text ,we know that on the earth _____

    A．there is air everywhere

    B．some animals don’t need air

    C．plants need more air

    D．for a long time people don’t need air.

    2.The writer tells us that _____.

    A．there is less air on the earth than on the moon.

    B．the earth is covered with water

    C．the earth is covered with air

    D．there is no air on the earth.

    3.Which of the following things need air ?

    A．land

    B．A mziror

    C．A cat

    D．A river.

    4.Which of the flooowing is the first important thing for people’s lives ?

    A．water

    B．air

    C．food

    D．sunlight .

    5.A man needs more air when he _____.  

    A．dies

    B．runs fast

    C．takes a rest

    D．sleeps

     

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    Water is very important to living things．Without water there can be no life on the earth．All animals and plants need water．Man also needs water．We need water to drink．to cool our food and to clean ourselves．Water is needed in offices，factories and schools．
    Water is needed everywhere．There is water in seas；rivers and lakes ,Water is found almost everywhere．Even in the driest part of the world．there is some water in the air．You cannot see or feel it when it is a part of the air．The water in the seas，rivers and lakes is a liquid。The water in the air is a gas，and we call it water vapor．
    Clouds are made of water．They may be made of very small drops of water．They may also be made of snow crystals(结晶体)．Snow crystals are very，very small crystals of ice．Ice is frozen water．It is a solid．There can be snow and ice everywhere in winter．
    (   )4．Where Can we find water?
    A．We can find water when it turns into vapor．
    B．Water can be found almost everywhere
    C．We can see water in deserts here and there．
    D．Water is only in seas and rivers．
    (   )5．We must protect water resources because       ．
    A．crops need water        B．all living things need water
    C．all animals need water    D．all plants need water

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