单项选择题
A．unless B．until C．before D．although
A．rely on traditional assumptions about earning and spending B．try to encourage or discourage consumers to spend money C．carry out investigations on consumer behavior and obtain data on consumers’ incomes and money spending motives D．do researches in consumer psychology in a laboratory
A．The relationship between education and economy, B．The relationship between high schools and universities. C．American education is not as terrible as many claim. D．The conventional ideas of U.S. technology.