issue: Competition for high grades seriously limits the quality of learning at all levels of education.
　　argument: "Butter has now been replaced by margarine in Happy Pancake House restaurants throughout the southwestern United States. Only about 2 percent of customers have complained, indicating that an average of 98 people out of 100 are happy with the change. Furthermore, many severs have reported that a number of customers who ask for butter do not complain when they are given margarine instead. Clearly, either these customers cannot distinguish butter from margarine or they use the term "butter" to refer to either butter or margarine. Thus, we predict that Happy Pancake House will be able to increase profits dramatically if we extend this cost saving change to all our restaurants in the southeast and northeast as well."