Hi, sorry for the slow reply as I’ve been away – ‘complimentary’ here would mean a detail that builds on/supports/goes with the first detail, as used earlier in the article. This construction in general is about combining complimentary elements, presenting one detail and then pairing it with another that goes with the first.

I think that would generally be fair to say but there are no real absolutes here, as I said above it’d be more to do with the length of sentence, phrase or clause that determines how useful a comma would be, really it’s just to help with clarity. E.g. “They not only danced but they also sang.” looks fine because we have too short clauses, but “He not only had long, dark, curly hair, but also the most lovely blue eyes.” reads better because we have long noun clauses. (Though equally it might merely depend on a style choice for consistency, i.e. if we chose always to use a comma with this construction.)

I understand that a comma is used when two independent clauses are connected with “not only … but also,” but if joining similar structures like 2 nouns, 2 adjectives, or 2 phrases in that case no comma is needed.

Hi Sydul, both these forms are possible; where we position ‘not only’ is quite flexible. However, you should quantify health, e.g. ‘my health’.

Which one is correct
I have to not only work hard but also take care of health.

I not only have to nwork hard but also take care of health.

Hi Rebanta,
There isn’t a hard rule here, but in general if you are connecting two phrases without a verb (e.g. nouns or adjectives) then a comma shouldn’t be used, but if you’re connecting two clauses then a comma should be used. But there may be exceptions in both cases – for example you might use a comma between two nouns to add emphasis.

Hi Zalak – to some degree this could be done as a matter of taste/style; I imagine in some regions English speakers will have a preference for one or another without affecting meaning. But as a general grammatical point, I would suggest that putting ‘not only’ before the verb suggests that the verb is what is being contrasted, so the extra detail following ‘but also’ should concern a verb.
E.g.
I not only walk to school, but I walk home too. (putting emphasis in both cases on the walking)
I not only washed the car, but I also cut the grass. (emphasising two different actions, washing and cutting)
Compare this last one to:
I washed not only the car, but also the windows. (emphasising what was washed)