A. ranking should be based on position, title or qualification.

B. scientific research papers should be signed with real names.

C. the signature should be under the title.

D. there should be spaces between names.

A: A.

Analysis: If there are more than two authors, the authors are generally ranked according to the number of people involved in the research work and the actual contribution, and the main authors are required to rank first, and the ranking order is not affected by positions, titles, qualifications or other factors. The importance of the title.

Related knowledge: The titles of scientific papers are also called "titles", "titles" or "titles". Some titles also include subheadings or quotations. A paper usually has several paragraph titles, also known as hierarchical titles or subheadings. Titles are symbols, titles are not sentences, they are more concise than sentences.

China's national standard GB77 13-87 stipulates: "The title is a logical combination that reflects the most important specific content in the report and paper with the most appropriate and concise words. Every word used in the title must take into account the specific practical information that is helpful to the selection of keywords and the compilation of secondary documents such as titles and indexes. The title should avoid using uncommon abbreviations, acronyms, characters, codes and formulas. Titles generally do not exceed 20 words. Reports and papers used for foreign exchange should have foreign language titles (mostly in English). Generally speaking, foreign book titles should not exceed 10 notional words ". No matter whether the reader comes into contact with a paper from a retrieval tool or a periodical catalogue, the title of the paper is the reader's first contact. Judging whether a paper is worth reading also begins with the title. If the title is improper, the readers who need it will not read it, thus losing its due role. In addition, both the index and the abstract depend on the correctness of the title of the paper. If the title is inappropriate, readers may not be able to retrieve it. Using keywords in the Internet or other computer retrieval systems may detect a large number of documents, and readers generally choose papers by browsing their titles. In order to win readers for the article, the report and the application for research fund, we must consider the proposed title of the paper. It can be seen that the title of a scientific paper is very important.