问题：

[共享题干题]阅读下面材料，回答下列的问题：     The Changing Middle Cla     The United States perceives itself to be a middle-class nation. However, middleclass is not a real designation, nor does it carry privileges (特权).It is more of a perception, which probably was as true as it ever could beright after World War II. The economy was growing, more and more people ownedtheir own homes, workers had solid contracts with the companies that employedthem, and nearly everyone who wanted a higher education could have one. Successful people enjoyed upward social mobility. They may have started out poor, but theycould become rich. Successful people also found that they had greatergeographic mobility. In other words, they found themselves moving to and livingin a variety of places.     The middle class collectively holds several values and principles. One strong valueis the need to earn enough money to feel that one can determine one's owneconomic fate. In addition, middle-class morality (道德观)embraces principles of individual responsibility, importance of family,obligations to others, and believing in something outside oneself. But in the 1990s those in the middle class found that there was a price for success. AU. S. News & World Report survey in 1994 indicated that 75 percent ofAmericans believed that middle class families could no longer make ends meet.Both spouses now worked, as did some of the children; long commutes becameroutine; the need for child care put strains on the family; and public schoolswere not as good as they once were. Members of the middle class were no longer financing their lifestyles through earnings but were using credit to stayafloat. The understanding of just what middle class meant was changing. 
不定项选择题第1题One important middle-class value is that
A.peopleshould always have fun
B.children should believe in themselve
C.debtis nothing to worry about
D.theyshould earn enough to finance their lifestyles