Many university classes nowadays have adopted the active learning(AL)style.AL is conducted through various techniques.In this report,we focus on exercises during lessons in class.We propose that teachers should know how students work on exercises in order to be able to give more effective support to students on these lessons.In order to investigate how students work on exercises,we used digital pens to collect data on their writing process using those pens and analyzed the data.The results showed that the students writing process had two important features: making attempts at exercises during explanation of the theme by the teacher,and adding other answers during group-work or explanation by the teacher after answering.