会计中的cost centre/ cost unit/ cost driver三者如何分？

书上的.定义：
cost centre: collecting places for costs before they are further analyzed.
cost unit: a unit of product or service to which cost can be related.
cost driver: a factor which causes a change in the cost of an activity
看定义好像都看得懂，但理解起来很吃力。能不能有比较具体透彻的解释？