Explanation:
A. It may constitute a conflicting application against other people’s subsequent applications. correct.
Part 2, Chapter 3, 2.2 of the Patent Examination Guidelines. In the judgment of the novelty of an invention or utility model, any unit or individual shall submit a request to the Patent Office for the same invention or utility model before the filing date and submit the application to the Patent Office before the filing date. Patent application documents published after the filing date (including the filing date) or published patent documents that damage the novelty of the patent application filed on that filing date are called conflicting applications. Therefore, as long as the conditions are met, it may constitute a conflicting application.
B. Make the invention for which a patent is applied for an existing technology. correct.
Patents trade disclosure for protection. When a patent application document is published, it becomes available to the public and becomes current technology.
C. The patent applicant can prohibit others from using the patent. mistake.
Publication of an invention patent does not mean authorization, so it is not protected by patent law at this time and has no right to prohibit others from using it.
D. Patent applicants can require units using the same technology to pay appropriate fees. mistake.
Article 10 of the Patent Law: After the invention patent application is published, the applicant may require the unit or individual who implemented the invention to pay appropriate fees. Option D is "units using the same technology", please read the question carefully.
To sum up, choose AB.