Graduate? I don't know (4)
I believe the answer is:
pass
This clue is a double definition.
'graduate?' is the first definition.
(pass the exam)
'i don't know' is the second definition.
('pass' is said to skip a question)
(Other definitions for pass that I've seen before include "Exceed; mountain route" , "Expression of ignorance" , "Cross-mountain route; permit" , "Mountain road" , "Transfer" .)