bill: what i'm trying to say is that each of us should blame ourselves for the tons of waste we produce every day.
andy: that's right, and some kinds of waste will take years to disappear. if i've understood correctly, using glass bottles could be a good alternative because it's possible to recycle them.
bill: and we should also consider alternative energy sources.
andy: can you clarify that?
bill: in other words, renewable energy comes from natural resources like the sun or the wind, which are always available and inexhaustible.