"Twelve is a dozen."
Translation:Zwölf sind ein Dutzend.
This is a tricky question. These do not appear that often.
If theres a predicative nominative that has a different numerus, then theres a strong tendency that the verb gets a plural inflection, but rarely you also see constructions with singular verb inflections.
So my advice is, if the subject is not 100% clear, then you should use a plural inflected verb. Most of the time it is not clearly distinguishable what the predicative noun shall be and what the subject noun shall be. Both come in nominative and they do not have a set place in the word order (so they can switch their places).
canoo states it in a similar way http://www.canoo.net/services/OnlineGrammar/Wort/Verb/Numerus-Person/ProblemNum.html?MenuId=Word21213#Anchor-Subjekt-11481
Wenn Subjekt und Gleichsetzungsnominativ in einem Satz nicht den gleichen Numerus haben, steht das finite Verb in der Regel im Plural:
Duolingo, please address this!
The phrase is, "Twelve is a dozen". The statement could also be said, "Twelve equals one dozen".
In this English statement, the number "Twelve" is an independent singular subject not an amount/quantity of something. The phrase is equating the number 12 to the quantity of one "dozen", else it would have included a subject (well, 12 of them actually)
"Twelve donuts are a dozen" would be referring to 12 independent donuts in a group. But, when the subject is the singular number "twelve" and not donuts, then "Twelve IS a dozen" is correct.
"Twelve are a dozen" is just simply wrong in every language. That is, unless, a subject is being implied in the statement:
"How many eggs are in a dozen?" (We are talking about eggs)
"Twelve [eggs] are a dozen." (The eggs are the implied subject, and "Twelve" becomes a quantity, not the subject.)
From Duo's correct answer, "Zwölf sind ein Dutzend", apparently they are implying 12 items/subjects in this sentence. Otherwise, it is wrong grammar.
And, as someone else pointed out, "Neunzehn ist eine Nummer/Zahl", is another version of this statement. Let's combine the two; "Zwölf ist eine Nummer"....Twelve IS a number. (again, Is not Are)
So, Duo, can you please try to make "Zwölf sind eine Nummer" or "Neunzehn sind kein Dutzend" correct statements...
For now, just do what Duo wants and move on to other lessons. Good luck!
I wrote "Zwölf ist ein Dutzend" and I believe that would be correct here. Other sentences in the exercise are "Nineteen is a number" - "Neunzehn ist eine Nummer/Zahl", so I believe when numbers are talked about like this they are a singular object/idea and the verb should reflect that. If for some reason the person was talking about eggs or something else and it was implied, it should be "Zwölf (Eier) sind ein Dutzend" but with no context in the examples, it's impossible to know which would be correct.
Apparently German is an exception regarding " Zwölf" sind ein Dutzend. In Spanish we say as in English "doce es una docena" using the 3rd person singular instead of the 3rd person plural. I guess we have to memorize it. However if we use a qualifier like "twelve cats are a dozen of cats" we have to use the 3rd person plural obviously.
Well, I have rarely heard 'doce es una docena' plus never used it myself in either Spanish nor Catalan, and I've been surrounded by both languages all of my life. Almost every time, I've heard (and used) 'doce son una docena' or 'dotze son una dotzena', both using the 3rd person plural.
I live in Spain, I suppose it might be used differently in other Spanish-speaking countries. Don't really know much about that.
So, in case it can help anyone, the 3rd person plural is often used in both Spanish (in Spain, at least) and Catalan when forming these kind of sentences.
I'm Catalan as well, and I don't believe this is the case at all. Same as any other language (perhaps other than German), the verb in 3rd person plural implies one refers to "twelve things" (e.g., doce [huevos] son una docena / dotze [ous] són una dotzena --- twelve [eggs] are a dozen). But without context, twelve is just a name referring to a number, and we would use the 3rd person singular to talk about it (e.g., doce es una docena /dotze és una dotzena --- twelve is a dozen). I don't see Spanish or Catalan behaving different to other languages in this regard. Both singular and plural are correct, but the plural requires context that is missing in Duolingo's questions.
Well, that might be what's 'correct' in the sense of what the rules state. Never said it isn't, I just meant to share my experience with the language.
I guess usage of these constructions can also be realated to how languages are spoken in different regions and personal preferences.
Again, if what you explained is the normative way to use it, then I supose that's what we should go with, but I have hardly came across with it in real life.
Thanks for sharing as it will sure be useful around here :) Hope you are doing fine :D