If + present, present for facts + things that are always true If you eat healthily, you lose weight If you heat up ice, it melts and then boils. If + present, future: for real situations that are possible in the future If you pass your English exam, you will get a job. If we get a vaccine, we will fight the virus. If + past, would + infinitive: for imaginary situations + for giving advice + unlikely possibilities If she won the lottery, she would buy a big house. If I lived in the countryside, I would be healthier. If I were you, I would ask the CAB for help. If I ran ten miles every day, I would lose weight. If + past perfect, would have + past participle for imagined past event + its results If I had arrived earlier, I would have learned more. If she hadn't wasted her time at school, she would have got a better job.