Sure! Here are the rewritten sentences:

39. Living in a big city is more convenient than living in a village.
=> It's more convenient to live in a big city than in a village.

40. Lisa is a more careful painter than her brother.
=> Lisa paints more carefully than her brother.

41. This solution is simpler than the last one.
=> This solution is simpler than the previous one.

42. My sister is a slower runner than I am.
=> I am a faster runner than my sister.

43. He adores playing Monopoly when he has leisure time.
=> He is fond of playing Monopoly in his free time.

44. The foreign language is so hard that I can't learn it.
=> The foreign language is not easy to learn.