9. 

1. He is the best football player in the world.

2. It's the most exciting game I have ever played.

3. My father is the most handsome man in my family.

4. Ngoc is the most pretty girl I have ever seen.

5. This movie is the most boring one I have ever watched.

6. This football match is the most wonderful match we have ever played.

7. Russia is the largest country in the world.

8. Which is the hottest continent in the world?

10. 

1. have⇒ has

2. have bought ⇒ bought

3. beautifulest ⇒ most beautiful

4. interesting most ⇒ most interesting

5. teach ⇒ taught

He is the best football player in the world

It was the most exciting game I have ever played

My father is the most handsome man in my family

Ngoc is the pretiest girl I have ever seen

This movie is the most boring one I've ever watched

This football match is the most wonderful match we have ever played

Russia is the largest country in the world

which is the hottest continent in the world?

She has never been to Korea

They bought an air conditioner yesterday

This is the most beautiful house I've ever seen

She told me the most interesting story for me

My father taught me how to use this machine