A man just to learn a foreign language,one day he walked on the street,accidentally stepped on a foreigner feet,and the man quickly said:"I'm sorry."the foreigner also polite said:" I'm sorry too." the man listened to said quickly :"I' m sorry three."the foreigner to be silly,asked:" What are you sorry for?" That person helplessly say:"I 'm sorry five." A man just to learn a foreign language,one day he walked on the street,accidentally stepped on a foreigner feet,and the man quickly said:"I'm sorry."the foreigner also polite said:" I'm sorry too." the man listened to said quickly :"I' m sorry three."the foreigner to be silly,asked:" What are you sorry for?" That person helplessly say:"I 'm sorry five."