This document discusses different types of if-clauses in English and provides examples to illustrate each type. It then provides exercises for learners to practice each type of if-clause. The three types are: 1. Type 1 uses simple present in if-clause and will-future in main clause to indicate a probable condition. 2. Type 2 uses simple past in if-clause and would + infinitive in main clause to indicate an improbable or unlikely condition. 3. Type 3 uses past perfect in if-clause and would have + past participle in main clause to indicate an impossible or unlikely condition.