The question is how far can we go in the use of coal for our energy needs since, for us, it is an imported energy source.
(it; is; an imported energy source) Context(it is,List([89, 94))):(The question; is; how far can we go in the use of coal for our energy)
it is,List([89, 94))
it The question
is is
an imported energy source
how far can we go in the use of coal for our energy