1. Which is the (long) river in the world ? 2. The (hot) country I've been to is Greece. 3. This exercise is the (easy) in the whole book. 4. The river Severn is the (long) river in Britain. 5. This is the difficult) exercise in the book. 6. China and India have the (important) populations in the world. 7. Baseball's the (popular) sport in America. 8. What's the (exciting) film you've ever seen? 9. My sister is the (kind) person I know in his life. 10. This party will be the (big)