This document discusses the 1st and 2nd conditional. The 1st conditional refers to possible or likely situations in the present or future, using "if" clauses with simple present or will future forms. Examples given are "If it's warm tomorrow, we'll go to the beach" and "If we don't hurry, we'll miss our bus." The 2nd conditional refers to unlikely or imaginary situations, using "if" clauses with simple past forms followed by "would" in the main clause. Examples provided are "If I won the lottery, I'd buy a big house" and "If he didn't have a car, he'd go by train."