Why can't we use the patent "as described in ……" in the process of writing? ....

First of all, the description "as described in the specification" cannot be used in the claim, which is stipulated in Article 26, paragraph 4, of the Patent Law and Article 18 of the Detailed Rules for the Implementation of the Patent Law;

Secondly, the description "as claimed" cannot appear in the specification, which is stipulated in Article 17 of the Detailed Rules for the Implementation of the Patent Law.

The patent law and the detailed rules for the implementation of the patent law are laws and are prohibited by law.

For details, please refer to the Patent Examination Guide.