Firstly, the ultimate goal of classes is not merely confined to master limited knowledge or prepare well for the final tests. In other words, under the professors guidance, not only can students grasp the pale knowledge points on the textbooks, but also they can equip with practical learning methods such as critical thinking method and brainstorming technique which are the most essential parts of classes and can not be acquired by students themselves. Limited knowledge imparted from professors is absolutely not enough for our future careers since knowledges are updated in such a frequent rate. Hence, only by learning the scientific studying methods from classes, can we always be competitive in job markets.