In Esperanto, we show the direct object of a sentence by adding an N. This lets us change the order of the parts of the sentence without changing the meaning. (A direct object is that which is directly acted upon by the verb)
La hundo amas la katon. - the dog loves the cat
La katon amas la hundo. - means the same thing because the N is still on the same noun.
Moving the N will change the meaning.
La kato amas la hundon. - the cat loves the dog.