太阳能是一种不污染环境的清洁能源。

Solar energy is a ___non-polluting source of power.

太阳能是一种不会污染环境的能源。

Solar power is a ___non-polluting source of energy.

电动汽车是一种无污染的交通工具。

Electric cars are a ___non-polluting mode of transportation.