This document discusses different types of conditional sentences in English. It explains the structure and uses of 1) first conditional sentences, which refer to possible present or future conditions based on fact, 2) second conditional sentences, which refer to unlikely or hypothetical present/future conditions, and 3) third conditional sentences, which refer to unlikely past conditions. It also covers structures using "unless", "in case", "wish", "if only", and "I'd rather" to express different types of hypothetical situations.

1. Conditional Sentences English I