... You don't need an 'auxiliary', such as 'do', 'does', 'did', or 'can'. "Can you tell me what you like most about your present job?" ... saying "Where is the police station?" (Not very polite), or "Do you know where the police station is?" (Slightly more polite), we could say: "You wouldn't know where ... semester. You can ask, "Weren't you in Professor X's history class last semester?" or "Were you in Professor X's history class last semester?" The meaning is...