Ответ:

Решение:

Распределим слова по категориям образования множественного числа.

-s-esirregular
students, chairs, beds, pouches, koalas, sheep, children, penguins, dolphins, tigers, feet, fish, women, geeseactresses, buses, addressesteeth, mice, man, foot

Ответ: -s: students, chairs, beds, pouches, koalas, sheep, children, penguins, dolphins, tigers, feet, fish, women, geese. -es: actresses, buses, addresses. irregular: teeth, mice, man, foot.