"Vera is the café's administrator."
Translation:Вера — администратор кафе.
You are indeed correct in that we use the genitive case here. However, кафе like many other imported words (кофе, такси, и так далее) is what we call an indeclinable noun, therefore the word doesn't change regardless of its case.
Another quick note - The genitive ending for neuter nouns ending in е, such as море, is я. You can take a look here for all of them. http://33.media.tumblr.com/5127b0b1aed2c5fd501d5ecc3a4747f3/tumblr_inline_mzgehrXN2T1qgkwq1.png
I put Вера кафе администратор and duo said that anwser is wrong, can you say it like that or do you have to say Вера администратор кафе? Can someone please explain, спасибо : )
[ Ка-фе́ ] is a Noun, not an Adjective. The [ кафе администратор ] phrase puts [ кафе ] in the context to perform as an adjective, modifying [ администратор ], what kind of administrator.
[ администратор кафе ] ‧ [ Administrator of the Café - literal grammar ] works because [ Ка-фе́ ] is able to function as the Noun that it is grammatically. Due to [ Ка-фе́ ]'s indeclinability, it is less obvious that [ администратор кафе ] has put [ Ка-фе́ ] in the Genitive Case.
[ Ка-фе́ ] is a borrowed word from French [ Café ] which borrowed from Arabic [ قهوة ‧ qahwa ]. Besides being indeclinable, I do not find a Russian [ Ка-фе́ ] adjective form, ala [ Ка-фе́ш-кий - just a made up word ]. A similar ancient Russian native term may likely have an associated adjective with the noun word.
[ Ка-фе́ш-ка ] is a declinable diminutive derived from [ Ка-фе́ ] but I do not find an Adjective form for it either. ‧ ru.wiktionary.org/wiki/кафешка ‧
Then how would you say that the administrator is in the cafe? I thought that "Администратор в кафе" would be that?