1. Conditional sentences What would you do if you saw a ghost in your house? By Mercedes Ramos 2. ZERO CONDITIONAL USE: It always happens If it rains, the ground gets wet If you heat water to 100 degrees, it boils Simple present if + simple present If + simple present, simple present 3. FIRST CONDITIONALCONDITIONAL USE: It is possible or easy to happen STRUCTURE: If + present simple, will + verb , can , may , imperative verb If you come early, we will go to the museum If you come early, we can go to the museum If you don't come late, you may come in If you come late, don't make any noise 4. SECOND CONDITIONAL USE: It is imaginary or difficult to happen STRUCTURE: If + simple past, would + verb , could + verb , might + verb If I were you, I wouldn't believe it If you saw an injured pet in the street, you could take it home If you were afraid, you might ask for help 5. THIRD CONDITIONAL USE: It is used for impossible actions because it refers to the past STRUCTURE: If + past perfect, would have + past participle If + past perfect, could / might + past participle. If you had come yesterday, you would have met my father If you had been frozen, could you have run? If you had wanted, you might have come with us 6. SHOULD IN CONDITIONAL SENTENCES By using should in the if-clause we are suggesting that something is unlikely or not particularly probable. If + subject + should + verb, subject + will + verb , subject + can + verb , subject + may + verb , verb / don't + verb If she should come, we will make a cake If you should visit your aunt, buy her a present If she should arrive, don't tell her any bad news 7. INVERSION IN CONDITIONAL SENTENCES In formal English, conditional sentences can be formed by inversion of the subject and the auxiliary verb. In such sentences, if is removed. Should he fail, don't tell him Were I cleverer, I would be happier Had I met him, we would have been friends Had we gone, we wouldn't have had an argument