Definition: An Article is a word prefixed to nouns, to point them out, and to show how far their signification extends; as, a book, an apple, the man. Japanese language doesn't have words for the articles "a", "an" or "the", but there is the Japanese word: その - Sono that means "that, those" and this could be translate as "the" and the Japanese word 一の-Ichi no for the articles "a" and "an".
Japanese Grammar is very special, because this language does'nt have grammatical accidents as: gender or number so articles are known as particles, it's the same to say "a book" or "the book"because it will be always 本 - (Hon) in Japanese language.
Lucy want to have an eagle.
Rūshī wa ichi no washi o motte iru to omoimasu.
She promised to bring the book of Japanese language.
Kanojo wa nihongo sono hon o motte suru koto o yakusoku shita.
Your dad have a new car.
Anata ichi no otōsan ga atarashii kuruma o motte imasu.
She'd like to have an apple to eat.
Kanojo wa tabete ichi no ringo o motte iru to omoimasu.
They buy the food for this week
Karera wa konshū sono shokuhin o kōnyū suru
Robert wants a new toy.
Robāto wa ichi no atarashii omocha o nozonde iru.