1. The Mekong River is the longest  river in VietNam. ( long )
2. Tokyo is  bigger than London. ( big )
3. Ho Chi Minh city is the biggest  city in VietNam. ( big )
4. Petronas Twin Towers is taller than Sears Tower. ( tall )
5. My sister is older than I. ( old )
6. Nam is shorter than Ba. He is the shortest  boy in VietNam. ( short ) 
7. Phanxipang is the highest mountain in VietNam. ( high )
8. These books are  thicker  than those books. ( thick )
9. It is the tallest  building in this city. ( tall )
10. The Nile River is longer than the Amazon River. ( long )