The document summarizes the different types of conditionals in English: 1) First conditional uses the present simple in the if-clause and will/won't in the main clause to talk about possible future events. 2) Second conditional uses the past simple in the if-clause and would in the main clause to talk about unlikely or hypothetical situations. 3) Third conditional uses the past perfect in the if-clause and would have + past participle in the main clause to speculate about different outcomes in the past. 4) Zero conditional uses the present simple in both clauses to express factual statements.