2. He was optimistic about the future, but his friend was pessimistic.
3. The smooth surface of the lake was disturbed by rough waves.
4. The ancient ruins were a stark contrast to the modern skyscrapers nearby.
5. She was loud and boisterous, while her brother was quiet and shy.
6. The expensive jewelry was a far cry from the cheap costume pieces.
7. The empty room was soon filled with crowds of people.
8. The artificial flowers looked remarkably like the real ones.
9. He was active and energetic, while his grandmother was inactive and slow.
10. The hard rock was impossible to break, but the soft clay was easily molded.
11. The dark hallway was lit by a single, bright lamp.
12. The complex instructions were confusing, but the simple explanation was easy to follow.
13. The thick fog obscured the view, while the thin air allowed for a clear sight.
14. His brave actions were a testament to his cowardly past.