fuel-wood, fire-wood, tree, wood, forest, heating, energy, firewood, material, raw, natural, renewable, source, warming, round, heap, stock, trunk, log, agriculture, alternate, alternative, climate, compatible, ecologically, effect, engine, environment, environmental, environmentally, fields, global, green, greenhouse-effect, nature, nonpolluting, oil, polluting, pollution, power, trees, turbine, wheel, wind, wind-energy, wind-engine, wind-farm, wind-mill, wind-power, wind-wheel, macromolecule, facility, nakedness, internal-combustion engine, achiever, woods, motor, station, mill, alternative energy, option, impurity, woody plant, mechanism, machine, field, cultivation, pile, capital, fuel, farming, vegetation, circular, plant, environmental condition, lipid, commerce, heat engine, molecule, rotary engine, choice, wind generation, power station, peer, production, mood, transaction, surrogate, industry, batch, person, mass, machinery, consequence, outcome, stand-in, replacement
fuel-wood and wind-wheels