Décommettre 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.
For all purpose but spelling,
battre and its derived verbs are conjugated like
rendre. The only difference is in spelling, as native French words may not have
tt before a consonant, thus the indicative present singular of these verbs goes
bats, bats, bat.
Mettre and its family show the same changes, but additionally have a past participle, past historic, and subjunctive imperfect in
mi-.
Décommettre is conjugated in interro-negative form. The interro-negative form being obtained by inversion of the subject, the placement of the negative adverb follow the same rules as in negative form, giving the following rules:
- in interro-negative form, the adverb
« ne » is always placed first if the subject is a pronoun.
- in simple tenses, the adverbs (
« ne ...pas »,
« ne...plus »,
« ne...jamais », etc...) surround the verb
décommettre and the inverted subject pronoun.
- in compound tenses or in ive voice, the negative adverbs surround the auxiliary and the inverted subject pronoun.
For sound reasons, like in interrogative form, 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 »:
« ne décommettra-t-il pas ">« n'aura-t-il pas décommis ? ».
Finally, the interrogative form does not exist in subjunctive and imperative.