#9

1) The Sahara Desert is the biggest desert on the Earth.

2) Mount Everest is is the highest mountain on the Earth.

3) The Nile is the longest river on the Earth.

4) The Great  Pyramid of Khufu is the tallest pyramid on the Earth.

5) the Pacific Ocean is the largest ocean on the Earth.

6) Australia is the smallest continent on the Earth.

7) The Dead Sea is the saltiest sea on the Earth.

8) Lake Baikal is the deepest lake on the Earth.

#8

1) Bird-watching is the most boring activity ever.

2) Reading is more interesting than watching cartoons.

3) Gardening is less interesting than doing sport.

4) Camping is as interesting as playing with friends.

5) Skateboarding is more interesting than fishing.

#3

1) The plane is more expensive than the horse.

2) The bus is more popular than the tram.

3) The trolley-bus is more popular than the camel.

4) The Underground is more interesting than the tram.

5) The camel is more unusual than the horse.

6) The bus is more dangerous than the plane.