Concept:
- When reporting a negative imperative sentence, the reporting verb 'said to' changes to 'told', and 'Don't + verb' changes to 'not to + verb'.
Step 1: Identify the sentence type
"Don't work too hard" is a negative imperative, an instruction telling someone not to do something.
Step 2: Convert the reporting verb
'Said to Joe' changes to 'told Joe' for reporting a direct instruction.
Step 3: Convert the negative command to infinitive form
'Don't work too hard' becomes 'not to work too hard' in indirect speech.
Step 4: Combine and check other options
"I told Joe not to work too hard" is the correct combination. The other options use wrong structures like 'asked...to work not for too hard' or add words that were never said, such as 'please' or changing the meaning to 'stop working'.
Final Answer: I told Joe not to work too hard.