Le conditionnel
The conditional is used to refer to things that are not certain: possible events. It is also used in polite requests and most frequently with if clauses. It’s most often translated by would in English.
Use the conditional:
1.Indicate that an action is possible if a condition is met (if...then). Sometimes you use a si clause for this: the conditional in one part of the sentence and si + imparfait in the other part.
2. To talk about possible events that have not happened.
3. To be polite. When mentioning a suggestion, a request, a wish, or to accept or extend invitations, use devoir, pouvoir, and vouloir in the conditional. It’s more polite than the imperative, which is used for commands and orders.
Formation
If you already know how to form the future simple and the imparfait the conditional is simple.
The conditional uses the same stem as the futur simple (usually the infinitive).
It uses the same endings as the imparfait. -ais, -ais, -ait, -ions, -iez, -aient
REMINDER: Verbs that are irregular for the futur simple use the same irregular stems in the conditional.
Here is a list of the most common irregular stems:
Some verbs with spelling changes in the present form their futur simple/conditionnel stem regularly. These include verbs like préférer, espérer, manger, and commencer.
Verbs with spelling changes like appeler, employer and acheter add -r to the present of the je form to create their future stem.
Quand and si and coordinating tenses (la concordance des temps)