Answer:
45. Everybody thinks that Ronaldo is a good football player,
a) It is said that Ronaldo is a good football player
b) Ronaldo is said to be a good football player.
46. They say that his books are still popular.
b) His books are said to be popular
47. They report that at least 10.000 dolphins are caught in the nets of tuna fishers every year.
b) At least 10.000 dolphins are said to be caught in the nets of tuna fishers every year.
48. They estimate that 1500 square kilometers of rainforests is cut every year.
b) 1500 square kilometers of rainforests are estimated to be cut every year.
49. We knew that pencil lead is made from graphite, clay, water and wax.
b) Pencil lead is said to be made from graphite, clay, water and wax.
50. They reported that the railway line was buried under tons of rock and earth.
b). It is said that the railway line was buried under tons of rock and earth.