Under the following circumstances, Party B acquired the ownership of the house on July 20 17 1 day?

(1) Article 209 of the Civil Code stipulates: "The establishment, alteration, transfer and extinction of the real right of immovable property shall take effect after being registered according to law; Without registration, it will not take effect, except as otherwise provided by law. " With regard to option A. The divorce judgment is final, and there is no need to register the ownership transfer for Party B. When the divorce judgment comes into effect, Party B obtains the ownership of the house. So I chose option a.

② About the B option. The judgment stated in option B is a valid payment judgment. When the judgment came into effect, Party B had not obtained the ownership of the house. On September 1 2007, when Party A completed the house transfer registration, Party B obtained the ownership of the house. So option b is not selected.

③ About the C option. According to Article 7 of the Interpretation of Property Rights in General Principles of Civil Law (1), the auction transaction ruled by the people's court in the execution procedure is a "formative judgment document", and the real estate does not need to be registered, and Party B obtains the ownership of the house from the time when the legal document takes effect. So I chose option C.

④ About the D option. The judgment in option D is "confirmed judgment", and Party B did not acquire the ownership of the house when the judgment came into effect, but acquired the ownership of the house from the date when the factual behavior was realized (the date when the house was capped). So I chose the d option.

To sum up, the correct answer to this question is ACD.