1. I didn’t eat lunch, I feel hungry now.
→ if i had eaten lunch, I wouldn't have been hungry now
2. I only come if they invite me.
→ unless they invite, I won't come
3.He didn’t revise all his lessons, he failed the exam.
→ if he had rivised all his lessons, he wouldn't have failed the exam
4. The park is over there, only 5 minutes walk.
→ if you walk for 5 minutes, you will find the park
5.. Leave me alone or I’ll call the police.
→ unless you leave me alone, I won't call the police
6. If you arrive at the office earlier than I do, please turn on the air-conditioner.
→ should you arrive at the office earlier than I do, please turn on the air-conditioner
7. The children don’t go to school in the snowy weather.
→ if it doesn't snow, the children will go to school
8.He died so young; otherwise, he would be a famous musician by now.
→ had it not been for his dead, he would have been a famous musician by now
9. You must tell me the whole truth or I won’t help you.
→ unless you tell me the whole truth, I will help you
10. The car breaks down so often because you don’t take good care of it.
→ were i take good care of it, the car wouldn't break down so often