English: Under what circumstances should an S be added after a word and under what circumstances should an es be added?

1. In general, add S; When the word ends with s, x, sh and ch, add es, but the plural form of stomach is stomachs；;

2. For words ending in S, Z, X, ch and sh, add the trailing -es at the end of the word to form a plural number;

3. For nouns ending in consonant letter +y, change Y to I, and then add-es;

4. For nouns ending in -o, if they are not loanwords or abbreviations, add -es; otherwise, add -s to form a plural;

5. Nouns ending in -is usually changed from -is to-es;

6. Nouns ending in -ix usually change -ix to -ices.