一个完型填空题

　　the work people do either provides what they need or provides the money with that they can buy essential commodities of course ,most people hope to have enough money to buy commodities and services which are essential but which provides some particular personal satisfaction. 其中with that that 应该改为WHICH但是为什么要这样改？什么样的情况下用which 什么样的情况下用that?