Перевести в reported speech (косвенная речь) 16. "don't argue with me," said the teacher to the boy. 17. "pull as hard as you can," he said to her. 18. "don't lend anything to her," he advised us. 19. "stand clear off the door," a voice warned the people. 20. "put down that gun. it's loaded," she warned him.

16 The teacher told the boy not to argue with him(her).
17He told her to pull as hard as she could.
18He advised us not to lend anything to her.
19A voice warned the people to stand clear off the door.
20She warned him to put down that gun.It was loaded.