1. Change the "y" to "ies".
Here are some examples:
* baby → babies
* city → cities
* story → stories
* fly → flies
* puppy → puppies
Exceptions:
* Proper nouns ending in "y" usually add only "s". For example, "Henry" remains "Henrys".
* Words ending in "quy" add only "s". For example, "soliloquy" becomes "soliloquies".