Cross your t's and dot your i's.
Do you know the table of 4's?
While most of our nouns form their plural in this regular way by adding s or es, there are some nouns that form their plural by some other change in the form of the word.
73. Notice the following list of words and their plurals:
fly
flies
city
cities
key
keys
day
days
story
stories
enemy
enemies
tray
trays
boy
boys
These nouns all end in y, yet they form the plural differently. Some simply add s and the rest change the y to i and add es. Can you discover the reason?
Wherever the y is preceded by a vowel, as e in key, a in tray, o in boy, the plural is formed by adding s. But when the y is preceded by a consonant, as l in fly, r in story, t in city, and m in enemy, the y is changed to i and es added in forming the plural.
If the singular ends inyafter a consonant, changeytoiand addesin the plural.
74. There are thirteen nouns ending in f and three in fe which form the plural in ves. They are:
All other nouns in f or fe are regular; adding only s, to form the plural.
75. About forty nouns ending in o after a consonant form the plural in es. The most common ones are:
buffalo
cargo
potato
tomato
negro
veto
cargo
echo
calico
embargo
hero
mulatto
mosquito
motto
tornado
volcano
torpedo
flamingo
Most nouns ending in o form the plural regularly, adding only s, as pianos, banjos, cameos, etc.
76. A few words form their plurals by a change in the word and without adding s or es.
The most common of these words are:
77. Proper nouns, when made plural, generally follow the same rule as common nouns. Thus we write:
All the Smiths, the Joneses, both the Miss Johnsons, one of the Dr. Davidsons, and the Mrs. Wilsons, were present.
But to prevent the confusion and misunderstanding which might arise in changing the form of a proper noun, we do not change its form in writing the plurals; for example: