Ответ:

  1. Listen to that music! Our neighbors shouldn't play music that loud at this hour.
  2. If your tooth is still hurting you tomorrow, you should go to the dentist's.
  3. Cathy shouldn't keep ringing her friend. I think it's a bad idea.
  4. Before going to Madrid for your holidays, you should try and learn something of the language. You will enjoy things a lot more.
  5. You should always knock on the door before entering. This is a private office.
  6. We shouldn't leave too late tomorrow if we want to reach the beach before lunch.