Today, moving and changing are as much a part of a modem businessman’s way of life as they were a part of the native American’s or the early pioneer’s way of life. And this trend is toward even greater mobility (移动), particularly within the management sector (层面) of American business. Since most jobs take only a year to a year and a half to master, in order to continue learning, most young people have to make a job change to strengthen their management training.