This document discusses different types of conditionals in English: zero conditional, first conditional, second conditional, third conditional, and mixed conditionals. It provides the form and use of each conditional. The zero conditional uses present tense to describe generally true events. The first conditional uses present/future tenses to talk about probable future events. The second conditional uses past tense to discuss unlikely or hypothetical present/future situations. The third conditional refers to impossible past situations using past perfect tense. Mixed conditionals combine different tenses across clauses.