1. Plural forms of nouns ending in -s, -sh, -ch, -gh and -th. -s, -sh, -ch ends with es, -th, -gh ends with s.

Second, end with-O. If there is no life, add S. For example, photo, radio, video, zoo, kilo and so on. Alive, plus es. For example: potatoes, tomatoes

Third, there are nouns that bring people.

(1) compound words. For example: British men-British men (English+men's synthesis)

② others. Germans-Germans-Germans-Germans-Germans-Germans.

Fourth, simple complex isomorphism.

Fifth, there is the plural form itself, that is, the simple plural is not the same meaning. Pay attention to clothes (about cloth, it means cloth, there is a difference. ) There are glasses, shoes, vegetables and so on.

Six, there is an a -s ending, which seems to be plural, but in fact it is a singular noun mathematics, mathematics, politics, physics and so on.