The simplest method of forming a plural is by adding –s or –es to the singular. Examples are: dog (singular)/dogs (plural), book/books, tree/trees, box/boxes and boy/boys
A few dozen nouns form their plurals irregularly.
Examples are: child/children, man/men, woman/women, tooth/teeth, mouse/mice, sheep/sheep, radius/radii, phenomenon/phenomena, bacterium/bacteria.
Some nouns are unusual in having only a singular form or only a plural form. Nouns which have only a singular form include furniture, wheat, happiness, gratitude, abuse, information, clothing, gossip, poetry, scenery, advice and news.
Nouns which have only a plural form include police, cattle, oats, tweezers, pants, remains, scissors, binoculars, shorts, trousers, drawers and socks. We cannot say a pant or a cattle, and we must say instead a pair of pants or a herd of cattle.
With some nouns, the plural is identical to the singular. Examples are: sheep, deer, swine, fish and salmon.
- This sheep is hungry.
- These sheep are hungry.
