Without giving a huge explanation, a conditional sentence has two parts: an "if" clause, and a "result" clause. The chances of the result happening relies on the "if" happening. We have four types: zero conditional (definite), first conditional (very likely), second conditional (unlikley, or vaguely possible) and third conditional (impossible). Each has their own pattern of grammar to indicate this. Have a search around and you'll find plenty of examples. If I wrote any more, this answer would be quite long. (<---ha!)

from where i can teach you? :)

thanks for your help :D would you like to describe me about first, second and third conditional sentences? huhuhu, i will get a test about it T.T