Recently, our environment is seriously polluted , so we need many ways to protect the environment . Firstly , do not litter indiscriminately , in stead of that , you can throw rubbish in the wastebasket . Secondly , retain plastic bottles after use , so we can recycle them to create a new gadget . Thirdly , we should encourage people to keep the environment clean by cleaning the streets around them , throwing  rubbish in the right places ,.... . Finally , we should plant more trees , because if there are more trees , the earth and the environment will be cleaner and greener .