The infinitive is one of the basic verb forms. The infinitive merely expresses the abstract idea of the action stated by the verb without any other shade of meaning: marcher (to walk), répondre (to answer). The ending (er, ir or re) indicates to which group the verb belongs (knowledge necessary for conjugation). Its two tenses are the present and the perfect.
Present Infinitive
The present infinitive, formed of the stem + er/ir/re (according to the group) is used to situate the action in the present or future:
Nous voulons
dormir.
(We want to sleep.) [now or later]
When an infinitive is negated, both ne and the second element of the negative precede the infinitive. However, personne (no one) and nulle part (nowhere) follow the infinitive.
Dans votre cas, il vaut mieux ne rien
dire.
(In your case, it would be better to say nothing.)
Usage:
When two verbs follow each other, the second verb must be in the
infinitive except when it follows the auxiliary verbs
être or avoir:
Nous
aimons rire et chanter.
(We like to laugh and sing.)
After the prepositions à (to), de (from), pour (in order to), sans (without):
Il commence à neiger. (It is
beginning to snow.)
Partez sans rien dire. (Leave without saying
anything.)
See also Prepositions.
To replace a whole subordinate clause:
Je vous vois rire. =
Je vous vois qui riez.
(I see you laugh.)
To shorten an interrogative clause:
Que dire? Que faire? = Qu'est-ce qu'il
faut dire? Qu'est-ce qu'il faut faire?
(What is one to say? What is one to do?)
To replace a noun and its article:
Nos chiens adorent courir. =
Nos chiens adorent la course.
(Our dogs love running.)
To replace the imperative in written notices, instructions:
Ouvrir avec soin. (Open with care.)
As a noun with an article or other modifier:
Le pouvoir corrompt. (Power corrupts).
L'homme doit faire son devoir. (Man must do his
duty.)
Perfect Infinitive
The perfect infinitive indicates that, at a given time, an action is/was completed. It is formed with the auxiliary in the infinitive form + the past participle:
avoir marché = to have walked.
Compare:
Merci de m'avoir apporté ce gâteau.
(Thank you for having brought this cake.)
Je suis
contente de vous voir ici.
(I am happy to see you here.)
It can replace subordinate clauses:
Il faut avoir vécu cette expérience pour la
comprendre. = Il faut que l'on ait vécu cette
expérience pour la comprendre.
(This experience must be lived to be understood.)
Replacing a noun:
Merci de m'avoir aidé. = Merci de
votre aide.
(Thank you for having helped me. = Thank you for your help.)
After pourquoi (why):
Pourquoi avoir
quitté si vite? = Pourquoi est-ce que vous avez
quitté si vite?
(Why did you give up so quickly?)
After a command or request, to indicate that an action must be completed by a given deadline:
Il faut avoir terminé avant ce soir.
(We must finish before this evening.)
See Also: