19. Possible answers:
• 1 She has been working too much / too long.
• 2 She has been painting.
• 3 He has been seeing ghosts.
• 4 They have been dancing / partying very late.
• 5 He has been reading too many books.
• 6 They have been studying hard.
• 7 They have been sunbathing for too long.
• 8 He has been walking too fast /carelessly.
• 9 She has been walking in the woods.
• 10 She has been peeling onions.
• 11 She has been reading a letter with sad news.
• 12 He has been playing golf wonderfully.
• 13 He has been dancing better than the others.
• 14 She has been singing very well.
• 15 He has been running the marathon.
• 16 He has been cutting the grass / mowing the lawn.
• 17 It has been snowing.