Summary

Here is a chart to help you to visualize the basic English conditionals. Do not take the 50% and 10% figures too literally. They are just to help you.

probability		conditional	example	time
100%		zero conditional	If you heat ice, it melts.	any time
50%		first conditional	If it rains, I will stay at home.	future
10%		second conditional	If I won the lottery, I would buy a car.	future
0%		third conditional	If I had won the lottery, I would have bought a car.	past