Maintenir is a french third group verb. So, this verb is irregular and do not follow a regular conjugation pattern like first or second group verbs. Follow this link to see all the endings of the conjugation of most of the third group verbs :
conjugation rules and endings for the second group verbs.
Verbs derived from
tenir and
venir form a major group of verbs who gains a
d in the future and conditional. These verbs are the only verb to have a nasal vowel in the past historic and imperfect subjunctive.
Maintenir verb is conjugated in female form and in reflexive form. Be careful, the past participle of compound tenses must agree with the subject.
Maintenir verb is conjugated in interrogative form. For sound reasons, an euphonious
« t » is added to the pronoun of the third person:
« il »,
« elle »,
« on »,
« ils »,
« elles » except when the verb ends with
« t » or
« d »:
« maintiendra-t-elle ">« aura-t-elle maintenu ? ».
Finally, the interrogative form does not exist in subjunctive and imperative.