Ответ:
1. If he sells some of his paintings, Van Gogh will gets some recognition during his lifetime.
2. If only John stopped instulting people.
3. If I were you, i would take part in this competition.
4. If I win the lottery, I will buy an expensive car. But that's almost(подмечу, не просто impossible, а almost impossible, не будь тут almost - предложение бы выглядело так: If I had wun the lottery, I would have bought an expensive car.) impossible.
5. I wish i spoke a foreign language. But i can.
6. If he fails the exam now, he will not get a place at university.
7. When it rains, the roads gets slippery and dangerous.
8. I wish I was rich.
9. I wish I got your message earlier.
10. If you had saved some money, you would have been able to go on holiday last year.