The second powerful factor influencing wages is a modern one: the professions protected by a strong union receive better salaries than those that are not unionized: construction workers are well paid, and so are plumbers, electricians, and truck drivers.

• 第二个影响工资的有力因素是现代才有的、受强有力的工会保护的职业比没有工会组织的工资要高：建筑工人工资高，管子工、电工和货车司机的工资也很高。