15. I will get a work permit. I will stay for another month.
If: If I get a work permit, I will stay for another month.

16. We won’t go out unless it stops raining.
If: If it doesn’t stop raining, we won’t go out.

17. He doesn’t take any exercises. He is so unhealthy.
Were: Were he to take any exercises, he wouldn’t be so unhealthy.

18. We can’t get the ticket because I don’t have the right change.
If: If I had the right change, we could get the ticket.

19. Study hard or you won’t pass the exam.
If: If you don’t study hard, you won’t pass the exam.

20. I didn’t eat lunch, I feel hungry now.
If: If I had eaten lunch, I wouldn’t feel hungry now.

21. I only come if they invite me.
Unless: Unless they invite me, I won’t come.

22.He didn’t revise all his lessons, he failed the exam.
Had: Had he revised all his lessons, he wouldn’t have failed the exam.

23. If you arrive at the office earlier than I do, please turn on the air-conditioner.
Should: Should you arrive at the office earlier than I do, please turn on the air-conditioner.

24. The children don’t go to school in the snowy weather.
If it: If it is snowy weather, the children don’t go to school.

25. He died so young; otherwise, he would be a famous musician by now.
Had: Had he not died so young, he would be a famous musician by now.

26. You must tell me the whole truth or I won’t help you.
Unless: Unless you tell me the whole truth, I won’t help you.