In the 1st semester of 2012, for the course of Elementary Analysis, we used our system of QDB to operate online-quizzes and online-exercises and also used an online-text. In the middle of the semester, we conducted an anquete to figure out if our online apparatuses are effective or not. To invesgate our theme, we could also utilize the usage record of online-exercises and the scores of online-quizzes of students. Analysing these data, we found that our system is efffective but have some problems. We argued how to solve the problems and to improve the system and its usage.