In Chinese culture, people believe some numbers are lucky or unlucky. This is to see what Chinese character the number sounds like. For example, the Chinese word for the number 8 sounds like the word for “making a fortune”. So, people think it is a very lucky number. Some people spend a lot of money to have 8s in their phone numbers. The opening time of the Beijing Olympics began at 8:08 p.m. on August 8, 2008.

    The number 9 is also a lucky number. It is something to do with the emperors of China. There were nine dragons on emperors' robes(龙袍). Today, 9 often stands for “long lasting”. That's why close friends always use 99 or 999 to describe their friendship.

    So what's a “bad luck” number in China? It might be 4. Many Chinese people see 4 as a “bad luck” number. Because it sounds like the Chinese character for “death”.

    Because of this, many buildings don't have the fourth floor, and just call it the fifth floor. In Hong Kong, some buildings even don't have all floors numbered with 4, such as, 4、14、24、34 and all 40-49 floors. Some buildings also don't have the 13^th floor as 13 is an unlucky number in the West. Now a question for you: How many floors are actually there if a building's highest floor is numbered 50?

我国最大的城市群位于（　　）

《中共中央关于制定国民经济和社会发展第十个五年计划的建议》指出，社会生产力的多层次性和所有制的多样性，是我国社会主义初级阶段的重要特征。我国建立在多层次生产力水平的基本经济制度是（   ）
①按劳分配为主体、多种分配方式并存                       ②以公有制为主体、多种所有制经济共同发展

③由社会主义性质和我国初级阶段的国情决定的       ④以公有制为主体、逐步全面取替非公有制经济在我国的发展