As already said, when an adjective or participle (or a noun) is added to
the object simply as a describing word, it takes "n" like the object, as
"Li perdis sian novan libron "("aux", sian libron novan), He lost his
new book. "Sxi trankviligis la kriegantan infanon "(aux, "la infanon
kriegantan"), She pacified the screaming child. "Li vizitis sian fraton
Johanon", He visited his brother John. ("John" shows "which" brother).
But if the adjective, participle, or noun is used not merely to
describe, but indirectly to tell something about the object, it does
not take "n". A comparison of the following sentences will make this
clear:--
1. Li trovis la pomojn maturajn. He found the ripe apples.
Li trovis la pomojn maturaj. He found (that) the apples (were) ripe.
2. Li trovis la krucxon rompitan. He found the broken jug.
Li trovis la krucxon rompita. He found (that) the jug (was) broken.
3. Li kolorigis la drapon rugxan. He dyed the red cloth.
Li kolorigis la drapon rugxa. He dyed the cloth red.
4. Li trancxis (aux faris) la veston tro mallongan.
He cut (or made) the too-short coat (the coat that was too short).
Li trancxis la veston tro mallonga.
He cut the coat (so that it was) too short.