Употребите существительное в форме множественного числа monkey

a monkey monkeys.

Plural of nouns is formed with the help of s or es. We add-es when nouns are finished by s, ss, sh, ch, x, o. When y comes after a consonant letter it changes into i+es. (a city cities).

Monkeys live in the jungle.

There are many monkeys in this Zoo.

We have seen many monkeys in the Zoo.

He trains monkeys in circus.

His monkeys can dance, drive bicycle.

His little brother likes to watch at monkeys.

There is a picture of huge monkeys in this book.