1."I must stay at home tomorrow," she said.
→ She said that she had to stay at home the next day.
2."The clock will never again if you try to repair it," the man said to Nam.
→ The man told Nam that the clock would never again if he tried to repair it.
3."I can't find my umbrella" she said.
→ She said that she couldn't find her umbrella.
4. they said:"we are learning English now".
→ They said that they were learning English then.