Stumped by this crossword clue? Unravel the mystery behind ‘Like some classes’!

1. Inspected, as a course
2. Checked out, in a way
3. Attended without being officially enrolled
4. Took a class unofficially
5. Listened in on a lecture
6. Participated in a course without receiving credit
7. Sat in on a college course
8. Registered for a class without the intention of obtaining a grade
9. Observed, as a college course
10. Participated in a class without being formally enrolled.