Déduire 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.
Déduire verb is conjugated in female form and in reflexive form. Be careful, the past participle of compound tenses must agree with the subject.
Déduire 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
déduire and the inverted subject pronoun.
- in compound tenses or in passive 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 déduira-t-elle pas ? »,
« n'a-t-elle pas déduit ? »,
« n'aura-t-elle pas déduit ? ».
Finally, the interrogative form does not exist in subjunctive and imperative.
