The river behind our house was very dirty in the past 改句保持句意

The river behind our house was very dirty in the past 改句保持句意 the river in front of my house was ,but it's clean now.改同义句： The river is behind our school同义句 1There was a river near the village in the past.同义句 The small river in front of my house was dirty before,but it The river (flow) past our town in the past The was an old building in front of our school（保持句意不变 our school has changed greatly in the past 3 years改同义句! 1,It happened that he was in the house at that time.(保持原句意思) The Nile is the longest river in Africa.(保持句意不变) 改句子：We should obey the rules in our school .(保持原句意思)We _____ she likes swimming in the river very much 同义句