I have a question about the word when. I have read that it can be a conjunction or a relative adverb (either way, it joins two clauses together). Can I ask how do I differentiate between the two?

A few sample sentences are:
1) He graduated from school when he was 22 years old.
2) The risk of theft is higher when you do not install a car alarm system.
3) I remember the day when we first met.

  • Related: ell.stackexchange.com/q/97882/99
    – Kris
    Commented Apr 11, 2018 at 6:30
  • Welcome to ELU. We are expected to put in some effort at finding the answer before posting here. Look at this: partofspeech.org/what-part-of-speech-is-when HTH.
    – Kris
    Commented Apr 11, 2018 at 6:31
  • In modern grammar, "when" is neither a conjunction nor an adverb in examples like yours, but a preposition. In the first two examples, "when he was 22 years old" / "when you do not install a car alarm system" are PPs functioning as temporal adjuncts. In the third, "when we first met" is a relative clause in which "when" has "day" as antecedent.
    – BillJ
    Commented Apr 11, 2018 at 8:07
  • Hi, thanks for the replies. I did actually do research, just that I’m confused by the things I read hence the post. Going by the previous post, it seems that when can be considered to be both a relative adverb or a conjunction. What I need to ascertain is when is “when” an adverb and when is it a conjunction instead? The first sentence in my example modifies a verb “graduated”, so is it an adverb here? The second sentence modifies “higher” which is an adjective, so does it means it’s an conjunction here? I can’t really see “when” as a preposition here.
    – Leoz
    Commented Apr 11, 2018 at 14:21
  • @kris after reading through the link you posted, I’m even more confused. There’s two sample sentences given: 1) Sunday is the day when I get my hair done. 2) raise your hand when you are done. It states that in 1) “when” modifies a verb, but what is the verb here? If the verb here is “is”, then for the second sentence “when” also modifies the verb “raise”, shouldn’t we label “when” as a adverb in both cases? Why would the second sentence be considered to be a conjunction instead? Sorry if I’m confusing you all, I’m pretty much confused myself. Thanks
    – Leoz
    Commented Apr 11, 2018 at 14:32