General Rule:
* Add "-s" to the end of the word:
* cat - cats
* dog - dogs
* book - books
Special Cases:
* Nouns ending in -s, -x, -ch, -sh: Add "-es":
* bus - buses
* box - boxes
* church - churches
* wish - wishes
* Nouns ending in -y preceded by a consonant: Change the "y" to "i" and add "-es":
* baby - babies
* city - cities
* story - stories
* Nouns ending in -y preceded by a vowel: Just add "-s":
* boy - boys
* monkey - monkeys
* toy - toys
Other Irregular Plurals:
Some nouns have irregular plurals that don't follow the usual rules. You'll need to learn these by heart:
* child - children
* man - men
* woman - women
* tooth - teeth
* mouse - mice
Let me know if you'd like more examples or have other specific questions!