Compléter Oceans and rivers1Version en ligne Fill in the gaps with the appropriate words. par Gabriel Pérez Comendador 1 moving Earth mass sea big smaller mass water Waves water down rivers An ocean is a of salt which covers a area of the surface of The . A sea is a of salt which covers a area . The water is always because of : ( caused by the wind ) . Currents ( they are like ) . Tides ( movements up and of the level of the ) .