This document discusses different types of conditional sentences in English. It outlines the structure and uses of 1) first, 2) second, and 3) third conditional sentences. The first conditional expresses possible conditions and their probable results based on present facts. The second conditional expresses hypothetical situations contrary to reality. The third conditional expresses hypothetical situations contrary to past reality. It also discusses the uses of "unless" and "in case", as well as structures using "wish", "if only", and "I'd rather" to express hypothetical meanings similar to the second and third conditionals.

1. Conditional Sentences English I