Choose the correct answer. 6. This river is ________ than that one. a) long b) longer c) longest 7. Mount Everest is the ________ mountain in the world. a) high b) higher c) highest 8. My bag is ________ than your bag. a) heavy b) heavier c) heaviest 9. Today is the ________ day of my life. a) happy b) happier c) happiest 10. Math is ________ than history for me. a) difficult b) more difficult c) most difficult