The primary disadvantage of fossil fuels is that they are more polluting than renewable energy sources.
(The primary disadvantage of fossil fuels; is; that they are more polluting than renewable energy sources) Context(The primary disadvantage of fossil fuels is,List([0, 43))):(they; are; more polluting than renewable energy sources)
The primary disadvantage of fossil fuels is,List([0, 43))
The primary disadvantage of fossil fuels they
is are
that they are more polluting than renewable energy sources
more polluting than renewable energy sources