1.4.4 Grammar Spot - Plural nouns

Plural nouns
1. In most nouns, add -s in the plural.
Examples: apples, cars, pictures
2. If the noun ends in -s, -ss, -sh, or -ch, add -es.
Examples: bus - buses, glass - glasses, wish - wishes, match - matches, echo - echoes, hero - heroes, potato - potatoes, tomato - tomatoes

radio - radios, piano - pianos, kilo - kilos
3. If the noun ends in a consonant + -y, the -y changes to -ies.
Examples: country - countries, party - parties.
But if the noun ends in a vowel + -y, the -y doesn't change.
Examples: key - keys, day - days.
4. Some nouns are irregular. This is shown in the dictionaries.
Examples: man - men, woman - women, child - children.
And now,listen!
Source: Soars, Liz and John. New Headway Elementary, Student's book. Third edition.