降低污染，保护环境500字作文

Our environment is very important for our lives 。 We need the fresh air， the clean water and so on 。 In the past， there were many trees around us ，the air was fresh and the river was clean。But now，people cut down many trees。 Air pollution and water polloution are very serious 。 The environment around us bees very terrible 。 We should protect our environment。 First， we should plant many trees to keep water。 Second ， we can ride a bike or walk to the school and work。。 Third ， we shouldn’t throw the dirty water into the river 。 Fourth， we shouldn’t use the plastic bags。 Finally， we can ask more people to join us