"Excuse me, what museum is that?"
Translation:Anteeksi, mikä museo tuo on?
So... let's put aside what the standard translations are in this course - millainen is of course taught as "what kind of..". But here I'm talking about the ambiguity of the English sentence: what answer would you expect to the question "what museum is that?" I can imagine both the answer "an art museum" (which would also be the answer to "which kind of museum"), or "the louvre" (which would also be the answer to "which museum is that"). So my thought is that both Finnish translations, mikä and millainen could work. But I admit that I'm not a native English speaker. Would be good to have their input on the meanings of the English sentence.
Questions to the Finnish natives: Would "an art museum" be an acceptable answer to the question "mikä..."?
In Finnish, the word order of "that is" (subject + copula) doesn't change, be it a statement or a question starting with an interrogative word. When on [is] becomes onko, to act as a question word, it comes before the subject.
"Mikä museo tuo on?" [What museum is that?]
"Tuo on taidemuseo" [That is an art museum]
"Onko tuo museo vanha?" [Is that museum old?]