Questions & Answers about Ben kütüphaneden bir kitap ödünç alıyorum.
Because Turkish verb endings usually already tell you the subject. In alıyorum, the ending means I am taking / I am borrowing, so ben is not strictly necessary.
So this sentence could also be:
Kütüphaneden bir kitap ödünç alıyorum.
Adding ben can give a little extra emphasis, contrast, or clarity, similar to I in English when you want to stress who is doing the action.
Kütüphaneden is kütüphane + the ablative suffix -den.
The ablative case often means from, out of, or away from. Here it marks the source of the book: the book is being borrowed from the library.
So:
- kütüphane = library
- kütüphaneden = from the library