There's a sea near our hometown,but the sea has been polluted which has been caused by the rubbish on the sea.It's so dirty that people do not swim here any longer.In recent years,the visitors have littered the rubbish,and the restaurant near the sea or the factories have discharged the waste water to the sea without being dealt with.In order to protect our sea,we should take action.First,we should let people know the importance of protecting the ocean.Second,we ban the visitors to litter the rubbish into the sea.Third,we don't allow the restaurants and factories to discharge the waste water into the sea.