1.If I had a spare ticket, I would be able to take you to the concert.
2.If she drank too much coffee,she wouldn`t feel calm.
3.If he was able to operate a computer,he would be able to type. или if he wasn`t able to operate a computer,he wouldn`t be able to type.
4. If they understood the problem, they would find a solution.или If they didn`t understand the problem, they wouldn`t find a solution
5. If you were able to run fast,you would be an Olympic champion. или If you weren`t able to run fast,you wouldn`t be an Olympic champion.