Japanese adjectives conjugate to become adverbs ... they become HAYAKU NARIMASHITA (have become early). As for NA adjectives, I'll explain with an adjective, JÔZU (to be good at) as an example.

NA-adjectives take NA after them ... This is an irregular conjugation, so you will just have to memorize it. To turn I-adjectives into the past negative, you change I to KU NAKATTA.