There are 14 grammar mistakes in the text on the right. You have to find them and correct them.
Click the word that you think is wrong, then write its correction in the box below.
A mistake may be a missing word. Click the space where you think the missing word should go, then write it in the box below.
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The    main    sources    of    energy    in    the    world   
is    fossil    fuels    -    coal,    oil    and    natural   
gas.    Fossil    fuels    are    non-renewable    -    this    mean   
that    nature    cannot    recreate    them    as    fast    as   
people    using    them    up    today.    Sometime    in    the   
future,    all    of    them    run    out    and    we   
will    need    other,    renewable,    sources    of    energy.    Some   
renewable    energy    sources    are    being    available    now.    One   
of    them    is    water,    what    has    been    used   
to    create    energy    for    thousands    of    years.    Today,   
hydro-    or    water    power,    generate    by    huge    dams,   
is    a    major    source    of    electricity    in    many   
parts    of    the    world.    But    the    hydropower    have   
its    own    costs.    When    dams    are    building    ,   
the    area    above    them    is    flooded,    sometimes    for   
miles.    In    some    places,    people    loses    their    homes   
as    well    as    the    rich    river    soil    in   
which    they    once    growed    their    crops.    In    other   
places,    wonderful    wild    landscapes    buried    forever    under    new,   
artificial    lakes.    Below    the    dams,    the    natural    habitats   
of    fish    and    wildlife    in    river    valley    is   
destroyed    as    the    course    of    the    river    is   
changed.