1. If he (pass) his examination, we’ll have a celebration. 2. What (happen) if I press this button?...

1. If he passes his examination, we’ll have a celebration. This is talking about a possible future event that depends on him passing the exam.
2. What will happen if I press this button? This is asking about the consequences of pressing the button.
3. If it is not raining now, we would go to the country. This is a hypothetical situation in the present.
4. If we had booked tickets beforehand, we would not have to wait now. This is talking about a different past outcome if something had been done differently.
5. If I were you, I would ring him up myself. This is giving advice in a hypothetical situation.
6. If you don’t give me more information, I won’t be able to help you. This is a condition for being able to help someone.
7. If it had not been so cold yesterday, we would have gone to the forest. This is talking about a different past outcome based on a condition.
8. If he were careful, he wouldn’t break things. This is talking about a general truth or advice.
9. If you hadn’t helped me, I wouldn’t have been able to finish the work yesterday. This is talking about a past situation and its outcome.
10. We won’t go to the theatre if he doesn’t bring the tickets. This is a condition for going to the theatre.
11. If he isn't at home, leave him a note. This is a plan of action based on a condition.
12. If you had learned the words, you wouldn’t have made so many mistakes. This is talking about a different past outcome.
13. If Ann were slimmer, she would be much more attractive. This is a hypothetical situation in the present.
14. If I had had a chance last year, I would have visited Great Britain. This is talking about a different past outcome.
15. I will let you know if he comes. This is about informing someone about a future event.
16. If you don’t hurry, you will miss the train. This is a warning about a possible future consequence.
17. I would buy this book if it weren't so expensive. This is talking about a condition for buying the book.
18. ‘Does she love him?’ ‘Of course she does. If she didn't love him, she wouldn't have married him.’ This is talking about a past decision based on love.
19. ‘What would you do if you saw a ghost?’ ‘I would run a mile.’ This is a hypothetical situation and response.
20. If I am not busy, I will visit you. This is a future plan based on a condition.

1. If he passes his examination, we’ll have a celebration.
2. What will happen if I press this button?
3. If it were not raining now, we would go to the country.
4. If we had booked tickets beforehand, we would not have to wait now.
5. If I were you, I would ring him up myself.
6. If you don’t give me more information, I will not be able to help you.
7. If it had not been so cold yesterday, we would have gone to the forest.
8. If he were careful, he would not break things.
9. If you had not helped me, I wouldn’t have been able to finish the work yesterday.
10. We won’t go to the theatre if he does not bring tickets.
11. If he is not at home, leave him a note.
12. If you had learnt the words, you would not have made so many mistakes.
13. If Ann were slimmer, she would be much more attractive.
14. If I had had a chance last year, I would have visited Great Britain.
15. I will let you know if he comes.
16. If you do not hurry, you’ll miss the train.
17. I would buy this book if it were not so expensive.
18. ‘Does she love him?’ ‘Of course she does. If she did not love him, she would not have married him.’
19. ‘What would you do if you saw a ghost?’ ‘I would run a mile.’
20. If I am not busy, I’ll visit you.

These sentences are corrected with appropriate verb forms based on the type of conditional sentence (first, second, third, or mixed conditionals) they represent, reflecting different situations of reality and hypothesis.