wide
renewed
traditional
resources
alternative
widely
exhaust
power
all the
There is now increasing concern about the world's energy (1)
particularly about
those involving fossil fuels. In less than a hundred years, we shall probably (2)
present sources of oil and gas. The world's coal reserves should last longer but, once used, these
cannot be (3)
It is important, therefore, that we should develop such (4)
sources of energy as solar energy as well as water and wind (5)
classed as renewable energy. Until these energy supplies are (6)
used, it is important for
developed countries to reduce energy consumption as much as possible.