46. This is the man. We are talking about his son.
- This is the man whose son we are talking about.

47. The view will take your breath away.
- What a breathtaking view!

48. The boy was so tired that he can't keep on walking.
- The boy was too tired to keep on walking.

49. They think that he worked very hard last year.
- He is thought to have worked very hard last year.