单项选择题A．To keep active at work.B．To prevent from seeing the doctor.C．To contract infectious diseases more easily.D．To enjoy the pleasures of life.

单项选择题A．Life-style of different people is the same.B．Different people may have completely different life-styles.C．It’s doubtful whether life-styles are changing.D．The changes of life-styles have’ no influence on business.