Duet
To sing in a duet in your dream signifies balance and harmony. You are coming to terms with some problem or issue that you have been at odds at for a long time.
To dream that you are being damned indicates that you need to use caution in a new situation. You are also overly concerned with what others think of you. Alternatively, if someone damns you in your dream, then it means that you need to be more thick skinned and not let others get to you so easily.
To dream of disappointment indicates real-life experiences of being continually disappointed. Such dreams often reflect repressed disappointments which has accumulated over a period of time. Your dream serves as an emotional outlet to help ease your mind.
To see an air duct in your dream represents an outlet to express your feelings. There is something that you want to get off your chest. If your dream involves seeing a lot of ducts, then it means that you are in control of your emotions. You channel your emotions and are cautious in how you express them.