The -oir verbs

Les verbes en -oir

the -oir verbs do not all follow the same conjugation pattern. We’ll start with the very useful verb savoir (to know). Savoir means to know a fact, to know how to do something from memory or study.

je sais -  I know
nous savons - we know
tu sais - you know
vous savez - you know
il/elle sait - he/she knows
ils/elles savent - they know
Elle sait jouer du piano.
She can play the piano.
Il sait ce poème par coeur.
He knows this poem by heart.
Ils savent gérer leurs affaires.
They know how to manage their business.
       Note that savoir is sometimes translated by can. Before a dependent clause or before an infinitive, only savoir can be used.
Je ne sais pas où il est.
I don’t know where he is.
Il sait qu’elle est occupée.
He knows she is busy.

When learning the verb savoir, you also need to become acquainted with the verb connaître, in order to understand when to use one or the other. Connaître means to know, to be acquainted with, to be familiar with. In a figurative way, it means to enjoy, to experience. It is always followed by a direct object; it is never followed by a dependent clause.
je connais - I know
nous connaissons - we know
tu connais - you know
vous connaissez - you know
il/elle connaît - he/she knows
ils/elles connaissent - they know
Elle connaît bien Paris.
She knows Paris well.
Connaissez-vous les Tavernier?
Do you know the Taverniers?
Son nouveau roman connaît un grand succès.
His new novel is enjoying great success.

The verbs pouvoir and vouloir
Pouvoir (can, may) expresses ability and capability.
Je peux -  Ican
Tu peux -  you can
il/elle peut -  he/she can
Nous pouvons  -  we can
Vous  pouvez -  you can
ils/elles peuvent -  they can  
Elle ne peut pas venir aujourd’hui.
She cannot come today.
Est-ce que tu peux lui téléphoner?
Can You call him?
Je peux vous donner des renseignements?
May I give you some information?
When asking permission with inversion in formal style, the first-person singular of pouvoir takes a different form.
Puis-je vous aider?
May I help You?
Puis-je vous donner un conseil?
May I give you a piece of advice?
Another formal way of asking questions is to use the conditional form of pouvoir. We’ll cover This in more depth in Chapter 12.
Pourriez-vous résoudre ce problème?
Could you solve this problem?
Pourriez-vous annuler notre vol?
Could you cancel our flight?
The e verb vouloir (to want) is used to express wishes and desires. It is also used for a polite request in the conditional form.
Je veux -  I want
Tu veux -  you want
Nous voulons -  we want
Vous voulez -  You want
il/elle veut -  he/she wants
ils/elles veulent - they want
Elle veut une augmentation.
She wants a raise.
Nous voulons une table près de la cheminée.
We want a table by the fireplace.
Je voudrais vous parler.
I would like to speak with you.
A number of other verbs ending in -oir are irregular. Let’s look at a few examples in their first-person singular and plural forms:
apercevoir to see, to perceive
j’aperçois I see, I perceive -  nous apercevons we see, we perceive
décevoir to disappoint
je déçois I disappoint - nous décevons we disappoint
devoir must, to have to
je dois I must, I have to - nous devons we must, we have to
émouvoir to move, to stir
j’émeus I move, I stir - nous émouvons we move, we stir
prévoir to foresee, to predict
je prévois I foresee - nous prévoyons we foresee
promouvoir to promote
je promeus I promote - nous promouvons we promote
recevoir to receive
je reçois I receive - nous recevons we receive
valoir to be worth
cela vaut it is worth - nous valons we are worth
voir to see
je vois I see - nous voyons we see