How do you form the conditional tense and when do you use it?

You use the conditional tense to:

- Say what would happen (e.g. I would eat an apple but I prefer grapes)

- Make a hypothesis (e.g. I would eat an apple if I had one)

-  Express a wish (e.g. I would like an apple)

- Make a suggestion (e.g. We could go to the shops to buy an apple)

Forming the conditional:

1. Take the stem of the future tense (infinitive minus the 'e' for 're' verbs, and just the infinitive for 'er' or 'ir' verbs)

2. Remember some verbs have an irregular future stem (e.g. aller uses 'ir', avoir uses 'aur' and être uses 'ser')

3. Add the imperfect endings: ais, ais, ait, ions, iez, aient (je/tu/il/nous/vous/ils)

Examples:

Aller --> j'irais, tu irais, il irait, nous irions, vous iriez, ils iraient 

Gagner --> je gagnerais, tu gagnerais, il gagnerait, nous gagnerions, vous gagneriez, ils gagneraient