The conditional is used to refer to hypothetical events. It occurs in polite requests and most frequently with if clauses. In French, it is called le conditionnel and is most commonly translated by would in English.
The stem used to form the conditional is the same as the stem of the future (usually the infinitive). The conditional endings are -ais, -ais, -ait, -ions, -iez, -aient (these are also the imperfect endings).
Verbs with irregular stems in the future will use the same irregular stems in the conditional. Here are the most common verbs that have irregular stems. Note that every single root for the future has an R.
The conditional is used to express a wish or a suggestion, to make a request, or to accept or extend invitations. It is less direct and more polite than the command form (or imperative). The verbs 'pouvoir', 'vouloir', and 'devoir' are often found in the conditional to diminish the strength of a command. In most cases, the conditional is translated as meaning would in English. However, je pourrais means 'I could', je devrais means 'I should' and je voudrais means 'I would like.'
Exercise. Give the conditional of the verb in parentheses in order to render the requests or invitations more polite.
Je _________________________ un café, s'il vous plaît. (vouloir)
_________________________ - tu aller au cinéma vendredi ? (aimer)
_________________________ - vous un thé avec moi ? (boire)
_________________________ - je avoir la clé de la voiture ? (pouvoir)
Est-ce que tu _________________________ la réponse à question numéro 5 ? (savoir)
Est-ce que vous _________________________ l'heure, s'il vous plaît ? (avoir)
Si tu étais libre, est-ce que tu _________________________ à ma fête ce weekend ? (venir)
Est-ce que Catherine _________________________ au restaurant avec nous si je l'invitais ? (aller)