Breakdown of Книга на удобном диване.
книга
book
на
on, at / by (transport) / to (a place) / to (in answer to)
диван
sofa, couch
удобный
comfortable / convenient
Questions & Answers about Книга на удобном диване.
Why is the adjective удобном instead of удобный?
The word на (on) points to a location, which means the words following it need to be in the Prepositional case. The dictionary form of this adjective is удобный. To match a masculine noun in the Prepositional case, the ending changes to -ом, making it удобном.
Why is there an -е at the end of диване?
Диван (sofa) is a masculine noun ending in a consonant. To show location in the Prepositional case after на, we add an -е to the end.
Why isn't there a word for "is" in the Russian sentence?
In Russian, the present tense of the verb "to be" (is, am, are) is almost always left out. The sentence literally translates to "Book on comfortable sofa."
Why use на instead of в here?
На means "on" (resting on a surface), while в means "in" or "inside". Since the book is on top of the sofa, we use на. Both prepositions trigger the Prepositional case when talking about where something is located.