Le conditionnel présent, et conditionnel passé

The conditional present and conditional past are very similar to words pairings of "would" and a "verb". For example, 'I would eat' and 'Je mangerais' have the same meaning. The conditional past, as the name suggests, has the same uses as the conditional present, but refers to something in the past. Ex 'J'avais mangé' is the same as 'I would have eaten.'

"Could, should and would"

When using the word could in English it can be one of two tenses, past and the English equivalent of the conditionnel tense.

a) When I was young, I could do this exercise
b) Could you help me tomorrow?

Identifying the tense can be difficult, to make things easier, try changing out the verb can with the words to be able to.

a) When I was young I was able to do this exercise
b) Would you be able to help me tomorrow?

Now it is clear that a) occurs in the past, and therefore should be translated using pouvoir in imparfait; we know this is true due to the use of the word 'was.' Conversely, b) should be translated into pouvoir with conditionnel. 

When using the word would, it is more polite to do conjugate it in the conditionnel tense versus another. It is similar so saying 'I would like something' versus 'I want something'; the latter is more demanding and in certain tones can sound rude.

For example
Je lui ai demandé poliment, mais il n'a pas voulu le faire
I asked politely, but he didn't want to do it

Je lui ai demandé poliment, mais il n'a pas voulu le faire
I asked politely, but he wouldn't do it

When using the word should in French, simply take the conditionnel form of devoir. Remember that when using devoir in other tenses it translates along the lines of 'to have to'.

Je devrais faire mes devoirs
I should do my homework

Je doit faire mes devoirs
I have to do my homework

Comment on utilise le conditionnel présent et passé

1. Premier choisissez un verbe
2. Prochain, conjuguez le verbe en le future simple et enlevez les terminaison.
3. Finalement, écrivez le nouvelle terminaison

Les choix sont

je/tu - ais
il/elle - ait
nous - ions
vous - iez
ils/elles - aient

Si tu veut conjugez un verbe en conditionnel passe tu devras faire les prochain étapes.

1. Premier choisissez un verbe
2. Prennez le verbe auxiliaire (avoir ou être) pour le verbe quand il est dans le passe compose
2. Prochain, conjuguez le verbe auxiliaire en le future simple et remplacer le terminaisons avec les terminaisons expliqué au-dessus.
3. Finalement, conjugez le verbe en le participe passé.