It's Pinkgreat. I'm here to ask you some questions.
1. What does "expert knowledge" mean?
2. Does 'all but' mean 'all without exception'?
Thanks in advance.
1 It means 'specialist knowl;edge', available to restricted people- you could know a lot about health, but a doctor will still have expert knowledge that you won't.
2 all but = very nearly- We all but failed = we passed, but could easily have failed