Our research aims at acquiring the knowledge to develop an effective system of support for revising written assignments, in order to assist students to compose logical sentences by themselves. We analyzed, quantitatively and qualitatively, the problems that arose in expository writing assignments, and the relevance of grade calculations. Furthermore, we also surveyed student attitudes toward written assignments in order to examine appropriate methods of support in the revision process. Expository writing texts are composed of a title, a body text, and a bibliography. The body text contains the definition of the theme, the reason for the choice of theme, questions that arise relating to the theme, exploration of these questions, and the conclusions. Our results demonstrated that the quality of the revised texts was influenced by the following factors: the length of the whole text, the section pertaining to the exploration of the research questions, and the bibliography.