Student or Learner
Hi are both compound nouns ok?
1) questions words
2) question words
In most cases, we use the singular form of the noun when it's used as a modifier, so use question words.
(Shoe store, hamburger stand, etc. One notable exception is sports. Sports car, sports stadium.)
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.