1. we must protect the factory form pouring waste water into the river2. we should stop people from throwing litter into the river.many kinds of litter may pollute the envirenment.3. we can tell the visitors how important the water is.4. we should save water in daily life.5. we need to protect the water resource.6. water pollution is mainly caused by the chemicals discharged by the factories. We should regulate the sewage discharge standard to minimize the impact of human activity on the environment.