Questions & Answers about Эта комната служит нам кухней.
Why is кухней in the Instrumental case?
The verb служить (to serve) is one of the verbs that requires the Instrumental case. When you want to say what role or function something serves, you put that noun in the Instrumental case. Here, кухня (kitchen) becomes кухней.
Where is the word for 'as' in this sentence?
There isn't one! In English, we say 'serves as a kitchen.' In Russian, the idea of acting 'as' something is built directly into the Instrumental case of кухней when used with the verb служить. You should not add a direct translation for 'as' (like как).
Why is нам in the Dative case here?
The verb служить takes the Dative case for the person or thing receiving the service. Literally, the room serves 'to us' as a kitchen. Therefore, мы (we) becomes the Dative нам.
Does this sentence imply the room isn't a real kitchen?
Yes, it often does. Saying Эта комната служит нам кухней implies that the room is functioning as a kitchen for you, even if it wasn't originally built to be one. If it were just a standard kitchen, you would usually just say Эта комната — наша кухня.