it’s polite to say “thank you” when others help us or say something kind to us. being polite is a good tradition in our country.nobody likes a person who is impolite. it’s important for us to be polite. we should say “thank you” to parents when they cook for us. we should say “thank you” when they wash clothes for us. we should also be polite at school. when the teachers help us work out questions ，we should say “thank you” to them. when we get bad grades and the teachers and classmates encourage us， we should say “thank you”. when someone open the door for us，we should say “thank you”. we should say “thank you” as often as possible.if everyone is polite to others，the world will be more and more beautiful.