Firstly, we must not throw garbage into the river and canals, because when we throw rubbish into the Canal, the Canal is filled with rotten garbage. People who go through this canal would be considered dirty.
First, we must not throw garbage into rivers. When we dump garbage into the canal. Canal is filled with rancid garbage. People who pass by will be seen as a dirty canal.
First, we must not waste into the river. Because when we waste into the canal. The canal was filled with garbage smell. Those who pass by will see this canal is dirty.