Infinitives in French, like their English counterparts are the non-conjugated forms of verbs. They are very important in that they provide the basis for all conjugations. Infinitives can be classified into 3 groups: verbs that end in -er, most verbs that end in -ir, and all other verbs. Verbs in the first 2 groups follow simple rules that once memorized really simplify conjugation exercises. Verbs in the 3rd group are all irregular, and even deceptive as they sometimes end like verbs in the other 2 groups. You will find more in lessons concerning those groups.
The gerund form of a verb is also called an “ing” verb because it is the form of verbs with “ing” endings, such as running, swimming, eating, etc. The gerund form of French verbs is constructed by adding the participe présent of a verb to the word “en.” (En courant / While running). Best translated as: “in the action of” + verb.
Participles are verb forms that can serve as adjectives or as building blocks for the composed forms of tenses. They follow simple rules in French.
Participe présent: verb root + –ant (Jouant / Playing)
Participe passé: generally, verb root + –é / –i / –u (J’ai couru. / I have run. – J’ai fini. / I have finished. – J’ai pleuré. / I have cried.).