Americans like to travel on their yearly holiday. Today, more and more travelers in the United States are spending nights at small houses or inns(客栈) instead of hotels. They get a room with breakfast the next morning.

    Rooms for the night in private(私人的) homes with breakfast have been popular with travelers in Europe for many years. In the past five or ten years, these bed and breakfast places have become popular in the United States. Many of these American's bed-and-breakfast inns are old historic buildings. Some bed-and-breakfast inns have only a few rooms, while others are much larger. Some inns do not provide telephones or televisions in the rooms, but others do.

    Staying at a bed-and-breakfast inn is much different from staying at a hotel. Usually the cost is much less. Staying at an inn is almost like visiting someone's home. The owners are glad to tell about the areas and the interesting places to visit. Many vacationers say that they enjoy the chance to meet local families.

①自觉为班集体做力所能及的事    ②当上班干部就好

③主动为班集体献计献策                ④只要学习好就是为建设优秀班集体做贡献了

14－16世纪是人和世界被发现的时代。“世界的发现”是指哪一事件（   ）