Épaissir is a french second group verb. So it follow the regular conjugation pattern of the second group like:
conjugation rules and endings for the second group verbs.
Épaissir is conjugated the same way that verbs that end in :
-ir. The prototypical verb for the second conjugation is
finir. The conjugation is, marked by the vowel
i and the infix
-iss- in the indicative present and imperfect.
Épaissir 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
épaissir 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 »:
« n'épaissira-t-il pas ">« n'aura-t-il pas épaissi ? ».
Finally, the interrogative form does not exist in subjunctive and imperative.