A.-The plural of a noun is usually made by adding "s" to the singular.
B.-Nouns ending in "o" or "ch", "sh", "ss" or "x" form their plural by adding "es".
But words of foreign origin or abbreviated words ending in "o" add "s" only.
C.- Nouns ending in "y" following a consonant form their plural by dropping the "y" and adding "ies" ( cons + y---> -ies)
Nouns ending "y" following a vowel form their plural adding "s" ( vowel + y ----> -s )
D.- Twelve nouns ending in "f" or "fe" drop the "f" or "fe" and add "ves".
calf / calves; life / lives; thief / thieves; half / halves; loaf / loaves; wife / wives; knife / knives; self / selves; wolf / wolves; leaf / leaves; sheaf / sheaves.
Exception: The noun "wharf" take either "s" or "ves" in the plural:
'wharfs' or 'wharves'
Other words ending in "f" or "fe" add "s" in the ordinary way: handkerchief / handkerchiefs; safe / safes.
1. A few nouns form their plural by a vowel change: tooth / teeth; foot / feet; man / men; woman / women; mouse / mice
2. Collective nouns, 'crew', 'family', 'team' etc., can take a singular or plural verb:
Our team is the best / Our team are wearing their new jerseys.
3. Certain words are always plural and take a plural verb: 'police'
4. Words plural form but singular in meaning: 'news': The news is good.
5. 'deer' and 'sheep' do not change: one sheep, two sheep
6. Certain nouns form their plural adding "en": ox / oxen; child / children
(THIS GRAMMAR SUBJECT IS NOT FINISHED. SEE SECOND LEVEL, EXERCISE ONE.)