The document discusses different types of conditionals in English grammar. It explains that conditionals describe possible results of present, future, or past situations. There are four types of conditionals: zero conditional, first conditional, second conditional, and third conditional. The zero conditional uses two simple present verbs to talk about results that always happen. The first conditional uses a simple present after "if" and a future simple to discuss possible future events. The second conditional describes impossible or unlikely present situations using the past simple after "if" and "would." Finally, the third conditional talks about imagined past results using the past perfect after "if" and "would have."