The type of question influences the interpretation I give to each card in the spread. It is usually something I am conscious of, perhaps deliberately producing. It is a driving force. The yin card, on the other hand, represents what is being left behind by the action of the yang card. This may be something I am not consciously aware of at all.
Every action has a reaction, every choice has consequences other than intended ones.
The two-card spread is a reminder that it is equally important to understand what must be acknowledged and released before change can really take place. Either way, it is also useful to bring in the techniques for interpreting a card pair . I think beginners can be confused and discouraged when the cards behave this way, and most books don't give any advice at all on handling it. In my version of the two-card spread, I have a nice metaphor for this situation. A passive card in the yang position implies a deliberate attention to something that is usually in the background.