3. Unlike regular schools, teachers cannot see their students in the online environment, so, above all, online students must A understand technical problems they meet in learning their courses B give their comments and request every clearly C. discuss their ideas according to their knowledge about the subject being studied 4,When problems arise, online students J月 A. explain their reasons for them and learn from other students B explain their experience with technical difficulties C. tell the instructors and other students what problems they have