"Today is my twentieth birthday."

Translation: Dnes mám dvacáté narozeniny.

[BoneheadBass]

My answer -- Dnes je mé dvacaté narozeniny -- was wrong. The correct translation offered was "Dnes jsou mé dvacáté narozeniny." I'll assume that the plural is used in the correct answer because "narozeniny" is plural, but I don't quite know why that is. In the English sentence, which is to be translated into Czech in this exercise, the subject is "today," not "birthday," which is why I used "je." Can someone help, please?

[VladaFu]

"Narozeniny" belongs to a category of words that are "pomnožná", plural-only or "plurale tantum" https://en.wikipedia.org/wiki/Plurale_tantum These exist in English as well. There is no singular *"narozenina" and it is weird to have one scissor or one trouser.

[BoneheadBass]

Thanks for your quick reply and for the explanation! I understand that "narozeniny" is a plural-only word, and I understand the often-used "to jsou" construction, which is somewhat confusing at first.

The problem here is that I don't understand why the verb in the correct translation that I was given matched "narozeniny" and not "dnes," since "today" (dnes) is the subject in the original sentence and was also the subject in my answer.

Oh, well. Maybe it will be safer to use "mít" as in the translation given at the top of this page... :-) Thanks again for your help.

[VladaFu]

Dnes can be either a noun or an adverb (specifying time). Here it is an adverb and the subject of the sentence is "narozeniny". And the verb agrees with the subject and is further specifies by the adverb.

[VladaFu]

Or actually, dnes is only an adverb. The noun is "dnešek".

[BoneheadBass]

AHA -- thank you so much for the additional info!

[Renardo_11]

In my opinion “dnes” (an adverb) is not the subject of the sentence; rather, “narozeniny” is. You can easily see that by replacing “dnes” by “on the twentieth” (dvacátého), which does not change the grammatical structure. Obviously, dvacátého cannot be the subject.

Edit: Thanks to Vlada for mentioning dnešek; I had overlooked that.

[Sam571287]

I put Dnes já mám dvacáté narozeniny, but that was marked wrong. Can you explain?

[AgnusOinas]

Just an unnatural word order. If you want to include (stress) "já" here, place it at the beginning for an "as for me" meaning: "Já dnes mám..." or "Já mám dnes..."

You could also place it at the end of the sentence (currently not accepted here) for a contrast-stress (it's not him whose birthday it is today, it's me!)