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      Tiny microbes (΢ÉúÎï)  are at the heart of a new agricultural technique to manage harmful greenhouse gas emissions. Scientists have discovered that microbes can be used to turn carbon dioxide into soil­enriching limestone(ʯ»ÒÑÒ)  with the help of a type of tree that grows in tropical areas, such as West Africa.

      Researchers have found that when the iroko tree is grown in dry, acidic soil and treated with a combination  of natural fungi(Õæ¾ú)  and other bacteria, not only does the tree grow well, it also produces mineral limestone in the soil around its roots.

    The iroko tree makes a mineral by combining calcium from the earth with carbon dioxide from the atmosphere. Bacteria then create the conditions under which this mineral turns into limestone. The discovery offers a new way to lock carbon dioxide into the soil, keeping it out of the atmosphere. In addition to storing carbon dioxide in the trees' leaves and in the form of limestone, the mineral in the soil makes it more suitable for agriculture.

       The discovery could lead to reforestation projects in tropical countries, and help reduce carbon dioxide emissions in the atmosphere in the developing world. It has already been used in West Africa and is being tested in Bolivia, Haiti and India.

    The findings were made in a three­year project involving researchers from the University of Edinburgh, Lausanne, Granada and Delft University of Technology.

    The project examined several microbiological methods for locking carbon dioxide as limestone, and the iroko­bacteria way showed the best results. Work was funded by the European Commission under the Future & Emerging Technologies (FET) scheme.

  Dr Bryne Ngwenya of the University of Edinburgh's School of Geosciences, who led the research, said, “By taking advantage of this natural limestone­producing process, we have a low­tech, safe and easily operating way to lock carbon dioxide out of the atmosphere, while improving farming conditions in tropical countries.”

1£®The passage mainly introduces ________.

  A£®some useful natural fungi and bacteria

  B£®a new way to deal with greenhouse gas emissions

  C£®a newly found tree in West Africa

  D£®the soil­enriching limestone created by scientists

2£®Which of the following is TRUE about tiny microbes?

    A£®Most tiny microbes like living in dry, acidic soil.

  B£®Carbon dioxide can be broken down by natural  fungi and bacteria.

 C£®The more greenhouse gas is, the more active   tiny microbes become.

 D£®Tiny microbes get along well with the iroko tree   in special soil.

3£®What does the underlined word “it” in Paragraph 3  probably refer to?

  A£®Carbon dioxide.        B£®Carbon.

C£®Soil.    D£®Limestone.

4£®According to the passage, what can we infer?

  A£®The action of the tiny microbes can increase the     oxygen in the earth.

  B£®Researchers have done the experiment on trees in    Africa for three years.

 C£®Researchers tend to use natural power to solve     their problems.

  D£®West Africa is one of the most polluted areas all     over the world.

5£®According to the passage, the iroko­bacteria  method ________.

   A£®can be used to improve the farming land

    B£®can save a lot of seriously destroyed woods

    C£®has been popularized in Bolivia, Haiti and India

     D£®should be spread all around the world in the future