Complete student history
If a student makes self corrections during the time the teacher goes over the assignment then cannot tell if the student turned it on time. Record unsubmit or both times it was turned in so teacher can keep track of assignments turned in on time.
For Assignments, you can see the history of the work, Open up the Assignment, select the students, and in the Grading Page, select View History.
For longer history in this view, you need to enable Insights. You can find more information about insights here