1. He knuckled down and focused on his studies in order to pass the exam.
2. The boxer knuckled his opponent in the jaw, knocking him out cold.
3. She nervously knuckled her fingers on the table while waiting for the interview to start.
4. The student knuckled the eraser on the pencil to get rid of the mistakes on his paper.
5. The toddler knuckled her eyes as she yawned and rubbed her face.
6. He knuckled the door loudly, hoping someone would let him in.
7. The chef knuckled the dough to make sure it was properly kneaded.
8. The child knuckled the toy truck across the floor, making engine noises as he played.
9. She knuckled her way through the crowd to get to the front of the line.
10. The athlete knuckled his injuries and continued to push through the pain to finish the race.