Answer:
1. If I had not hurt my ankle, I wouldn't have stopped running.
2. If only my friends liked to play team sports.
3. I wish I hadn't bought a car.
4. If only I hadn't dropped my fishing rod in the river.
5. James wishes he could take part in the competition.
Explanation:
The subjunctive mood is used to talk about imaginary or impossible situations, and to express regret. Sentence one makes use of Third Conditional, which is formed with the Past Perfect and would have + past participle. Finally, I wish and if only are used with the Past Simple to refer to an unlikely situation in the present, while the Past Perfect indicates regret over something that has already occurred.