The sudden raise/ rise in the cost of living proved to be an unforseen advantage.

Michelle Cha2.1. The sudden and unprecendented rise in the cost of living proved to be an unforseen advantage

Rise: an intransitive verb
Raise: a transitive verb

Mister Micawber Michelle Cha2.1. The sudden and unprecendented rise in the cost of living proved to be an unforseen advantageRise: an intransitive verbRaise: a transitive verb

In the given sentence, rise and raise are nouns I think.

Hi Michelle. In your sentence 1. which is not correct, you might have written "The cost of living was raised suddenly and unprecedentedly which proved ..." This shows that raise is a verb as in "The sun rises in the East". In 2.1. which is gramatically correct, rise is also the verb, you could have rephrased this as "The cost of living rose suddenly and unprecedentedly which proved ...".

CitiboxHowever, raise can be a noun as well, as in "I have just received a salary raise", but I believe this to be American and slang

It's not slang.

raise–n.
35. an increase in amount, as of wages: a raise in pay.
36. the amount o

Michelle ChaIn the given sentence, rise and raise are nouns I think.

Sorry—I'm in the midst of filling out my tax returns and am not very clear-headed. Anyway, I think that difference still applies indirectly, as 'rise' seems to me to be the only reasonable choice.

Thank you CB. I will give way to your superior knowledge but it does not appear in any of my dictionaries nor style guides so I am presuming it is more commonly use in the USA than in Britain.