Things to know about IF clauses

A. English

If I have the money, I will go with you. (certainty)

If I had the money, I would go with you. (doubt implied. I may not have the money.

If I had had the money, I would have gone with you. (opportunity missed)

B. Français

THESE ARE THE ONLY VERB FORMS TO BE USED WITH SI.

--> SI j'ai l'argent, j'irai avec vous. (présent --> futur)

--> SI j'avais l'argent, j'irais avec vous. (imparfait--> conditionnel)

--> SI j'avais eu l'argent, je serais allé(e) avec vous. (plus-que-parfait--> conditionnel passé