是这样的
在managerial ecnomics and business strategy第五版里
定义opportunity cost ：opportunity cost of using a resource includes both the explicit( or accounting ) cowt of the resource and the implicit cost of giving up the next-best alternative use of the resource.

这个定义我觉得没有问题
然后书举了这个例子

what does it cost you to read this book?
1. the price you paid the book store for this book
2....

问题在1上·~·这个也算是机会成本么？~！~！！
那么如果我投资一个产业所个花费的成本不也是机会成本了么？~~！！！
可是不该是这样的啊
机会成本不应该是说你放弃的那东西的value么