Answers: A, C, D

This question examines trademark registration and review, which is an important test point.

According to Article 8 of the Trademark Law, any mark that can distinguish the goods of a natural person, legal person or other organization from the goods of others, including words, graphics, letters, numbers, three-dimensional signs, colors Combinations, sounds, etc., as well as combinations of the above elements, can be applied for registration as trademarks. It can be seen from this that sounds can be registered as trademarks, so option A is correct. According to Article 22 of the Trademark Law, an applicant for trademark registration shall fill in the product category and product name of the trademark in accordance with the prescribed product classification table, and submit an application for registration. A trademark registration applicant can apply to register the same trademark for multiple categories of goods through one application. Therefore option B is wrong. According to Article 10, Item 1 of the Trademark Law, the following signs shall not be used as trademarks: (1) The country name, national flag, national emblem, national anthem, military flag, military emblem, military anthem, medals, etc. that are the same as the People’s Republic of China Identical or similar, as well as the same as the name or logo of a central state agency, the name of a specific place where it is located, or the name or graphics of a landmark building; therefore option C is correct. According to Article 14 of the Trademark Law, producers and operators are not allowed to use well-known trademarks on goods, product packaging or containers, or in advertising, exhibitions and other commercial activities. Therefore option D is correct.

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