Объяснение:
1 they have been discussing the problem for hours, but have not solved it yet.2 correct 3 is it still raining No, it has stopped. 4 John has won the championship twice .5 the boys have been fishing for 3 hours. 6 correct 7 correct 8 he has hated oranges since his childhood. 9 they have taken the dog for a walk. 10 Irene has left for the airport