Passage A
　　In front of many American houses you can see a mat.People sometimes call it a “welcome mat” because many of these mats have the word “welcome” on them.Some welcome mat have the family name on them, too.
　　Because Americans do not take off their shoes before they go into the house, they need a welcome mat to clean their shoes.If the children do not clean their shoes on the mat, their parents may not let them in.If you go to an American home, please remember to clean your shoes on the mat.
　　Always remember: “Different countries, different customs.”