资料题：According to the author, our environment is polluted by（　）。

When asked to point out of one or two things that are most important to themselves, many put friends ahead of homes, jobs, cloth and cars.A true friendship carries a long history of experience that determines who we are and keepsus connected.It is a treasure we should prove it.Unfortunately, the better friends you are, the more probably you'll have disagreements.And the result can be what you don' t want - an end to the relationship.The good news is that most troubled friendships can be mended.First, don't let your pride get in your way.Most of us can forgive each other when differences are brought out in the open.Second, apologize when you' re wrong - even if you've been wronged.Over the course of friendship, even the best people make mistakes.Sometimes, it may be best f the wronged person takes wrong.Third,see things from your friends' point of view.And finally, accept that friendship changes as our needs and lifestyle change.Making friends can sometimes seem easy.The hard part is keeping the connection strong during the natural ups and downs that have an effect on all relationships.My suggestion: Consider friendship an honor and a gift, and worth the effort to treasure and nurture.