The rules for regular plural nouns are: Just add an ‘s’ Add an 'es' Drop the ‘y’ and add ‘ies­’ Replace the ‘f’ or ‘fe’ ending with ‘ves’ Check your knowledge and find out ...

Mr. Ezersky carefully chose the other letters to limit plural opportunities. He omitted E and T, which commonly end words pluralized with S, and he included F and B to limit common words.