In the process of applying for a patent for invention, the examiner will make a preliminary examination and substantive examination of the patent application documents according to the application documents submitted by the applicant, with the main purpose of examining whether the application documents submitted by the applicant conform to the provisions of the Patent Law and its implementing rules. When defects that can be corrected are found, the examiner shall notify the applicant to eliminate the defects through correction to meet the publication conditions. When an insurmountable defect is found, the examiner makes an examination opinion, indicating the nature of the defect, and ends the examination and approval procedure as soon as possible by rejecting it. In addition, it is necessary to determine whether an application for a patent for invention should be granted a patent right, especially whether it conforms to the provisions of the Patent Law on "novelty, creativity and practicality". In this necessary process, the applicant may receive examination opinions many times, and the reply to the examination opinions will directly affect the process and result of patent application.