Learn Turkish: Binanın eski olduğunu biliyorum. - I know that the building is old.

Binanın eski olduğunu biliyorum.

I know that the building is old.

Breakdown of Binanın eski olduğunu biliyorum.

Questions & Answers about Binanın eski olduğunu biliyorum.

Why do we need the word olduğunu here if the English translation is just "that the building is old"?

In Turkish, complement clauses like "that [something is X]" require a verb to attach the factive suffix (-dık). Since eski (old) is an adjective and not a verb, we use olmak (to be) as a helper verb. So, eski olduğunu translates literally to "its being old".

Why is bina (building) in the genitive case as binanın?

In Turkish noun clauses, the subject of the inner clause ("the building") takes the genitive case (-nın). The verbal noun (olduk) then takes the matching possessive ending (-u). Grammatically, it is constructed just like a possessive compound phrase: "the building's being old".

What exactly are the suffixes attached to olduk to make olduğunu?

First, we have the verbal noun olduk. We add the 3rd person singular possessive -u (referring to binanın, which softens the k to ğ). Then we add the buffer -n- and the accusative case -u, because this entire clause is the specific direct object of the main verb biliyorum (I know).

Could I just say "Bina eski biliyorum" without using olduğunu?