Q:

I asked my sister if she had returned the mobile phone to her friend.

• 1
  I said to my sister, ‘have you returned the mobile phone to your friend?’
• 2
  I said to my sister, ‘did you return the mobile phone to my friend?’
• 3
  I said to my sister, ‘have you returned the mobile phone to my friend?’
• 4
  I asked my sister, ‘have you return the mobile phone to your friend?’