1. Students must have maintained F-1 status for one academic year to be eligible for CPT. 2. Part-time CPT is 20 hours a week or less. If done during school year, must maintain full time status. It has no effect on OPT. 3. Full-time CPT is more than 20 hours a week. If you do more than 12 months of full-time CPT, you lose your OPT option. 4. You need to be attending your school even when you are on CPT, else you lose your status. But you can talk to your professors and see if they will let you do self study, without attending the class, provided that you doo all assigbnments, projects and labs and appear in the exam as others do. They mostly let you do so. Its your job to convince that you will do well in studies.