I graduate May 2019. from 1yr advance course at Centennial.
2016, I did receive my PGWP.
my study permit expires 20/20
1.will my work permit expire or can i keep working 20hrs since my study permit expires 20/20?
After you finish your studies you are no longer a student and can not work on the study permit, study permit becomes invalid after finishing studies regardless on what it says on the piece of paper. So you need to get work permit to work afterwards.
Agreed with the above. You have to stop working as soon as you complete school. If you want to work after you graduate, you'll need to obtain a closed work permit which requires a job offer in Canada and approved LMIA from your employer.