Compléter Text energyVersion en ligne Fill in the gaps, choose the correct answer par Анна Пак 1 hydro cause important great solar This problem is very . 2 work energy free cause important The sun is a source of energy . 3 free use popular use work People coal to produce electricity . 4 cause change coal work panel Solar panels best in sunny places . 5 change work cause important use Wind turbines wind energy into electrical power . 6 free power cause plant solar Wind turbines no pollution .