Grade 3 Grammar Lesson 2 Nouns – singular and plural
If a vowel (a,e,i,o,u) comes before y, just add s to make the noun plural.
If a consonant comes before y, you change it to i and add es.
Add es to singular nouns ending in ch, sh, s and x to make them plural.
All nouns do not form their plural by adding s. Some nouns have their own plural form.