Упражнение 6. Correct the mistakes if any. 1. They are discussing the problem for hours, but has not solved it yet. 2. Somebody has been playing tennis since 2 o’clock. 3. Is it still raining? No, it have stopped. 4. John has been winning the championship two times. 5. The boys have fished for 3 hours. 6. How many books have you written? 7. Mike has invited many friends to his birthday party. 8. He has been hating oranges since his childhood. 9. They have been taken the dog for a walk. 10. Irene has left for the airport.