A solid big lock hung on the door, an iron stick made great effort to pen it, but failed. The key came, his tiny body entered the locked hole, opened it easily.The iron stick asked suprisely: why can not I open the lock with all my efforts, but you can do that so easy? The key said: because I know his heart most. Everyone’s heart is just like a locked door, no matter how thick the iron is, it can not open up the lock. Only care can turn yourself into a delicate key, enter into other’s heart and understand others. Only those who wear shoes know what’s wrong with the shoes.