It was not my first time to know the "opportunity cost".  After taking the lesson of “清华管理课程” , surprised to find the "opportunity cost" really impacted our decision - making - pattern.

Then i checked the definition of "opportunity cost"  - the benefit that could have been gained from an alternative use of the same resource 机会成本; 对同样资源非正统方式地利用所可能获得的益处.

In Confucius `s word,  if we decide to take the fish for lunch, absolutely we will miss the flavor of bear`s -paw. In another explaination, if we invest the capital to the stock,  we won`t receive other alternative investment benefit like real estates, etc. "Opportunity cost" is also a factor to help to evaluate the expecting value of continuous input.