"Their mother is good."
Translation:Ilia patrino estas bona.
bona is an adjective and bone is a adverb. every word ending in a is an adjective (describing a noun) every word ending in e is an adverb (describing a verb) every word ending in o is a noun no matter if feminine or masculine there are no grammatical genders. it is a kinda unnatural but when you get used to it, it gets easier