Can you please tell me whether it is correct or not to insert a comma before either in this sentence?
"Finally, the populations of Russia and Turkey did not show any alterations (,) either positive or negative."
I am neither a native speaker nor am I savvy in grammar. Hereby, I want to apologize beforehand, if the question will seem a little dumb. Thanks in advance!
Best Answer
I think it is correct to put a comma there. The comma separates Finally, the populations of Russia and Turkey did not show any alterations, which is the main clause, from either positive or negative, which is a non-defining relative clause (which adds extra information but can be removed without losing the meaning of the sentence).
Quoting from https://www.ef.co.uk/english-resources/english-grammar/non-defining-relative-clauses/,