阅读下面短文，掌握其大意，然后从1—15各题所给的A、B、C、D四个选项中，选出最佳选项。
Britain society is considered to be divided into three main groups of classes—the upper class, the middle class, and the lower or working class. This is known__1__the class system and it is important to know something about it if you want to__2__British people and society. Most British people grow up with a deep__3__and understanding of the class system even if they are not very conscious of it. __4__， most people know which class they belong to and are able to__5__which class other people come from by the way they__6__， the kind of clothes they wear, their interests and hobbies or__7__the type of food they eat.
