Множественное число существительных

+s
an apple-apples

+ES(if nouns ending in –s,-ss,
-ch,-x,-o)
a tomato-tomatoes

BUT:
radio-radios
piano-pianos
photo-photos
rhino-rhinos
hippo-hippos
video-videos

Nouns ending in a vowel+Y take –s in the plural
a toy-toys

Nouns ending in consonant+y, drop the –y and take –ies in the plural
a strawberry-strawberries
y-i+es

Nouns ending in –f or –fe, drop the f or fe and take –ves in the plural
a leaf-leaves
-f/-fe-v+es

BUT:
chiefs
roofs
safes
cliffs
beliefs
scarf(ves)
wharfs(ves)
dwarfs(ves)
hoofs(ves)

IRREGULAR PLURALS:
a man-men
a woman-women
a child-children
a foot-feet
a tooth-teeth
a goose-geese
a mouse-mice
a louse-lice
an ox-oxen

SOME NOUNS HAVE THE SAME singular and plural forms:
a fish-fish
a deer-deer
a sheep-sheep
a trout-trout
a swine-swine
an aircraft-aircraft
a means-means

Some words which come from foreign languages have special plurals:
Analysis-analyses
Appendix-appendices/appendixes
Bacterium-bacteria
Basis-bases
Cactus-cacti/cactuses
Crisis-crises
Criterion-criteria
Diagnosis-diagnoses
Formula-formulae/formulas
Fungus-fungi/funguses
Hypothesis-hypotheses
Medium-media/mediums
Phenomenon-phenomena

Noun+preposition+noun, we add –s to the first noun
a mother-in-law- mothers-in-law

If the first word is man or woman
a woman-doctor- women-doctors

Noun+adverb, we add –s to the first word
passer-by-passers-by

If there is no noun-stem in the compound –s is added to the last element
Forget-me-not-forget-me-nots

Uncountable nouns(are used in singular):

Always plural:
people arms
cattle ashes
trousers barracks
jeans clothes
shorts congratulations
shoes outskirts
gloves police
pajamas riches
tights stairs
earrings surroundings
scissors wages
pliers goods

A group of english nouns that can be used as countable or uncountable with a difference in meaning:

Collective nouns that can be both singular and plural:
Army
Audience
Class
Committee
Company
Crew
Crowd
Government
Group
Faculty
Family

TEam
Is singular when it is regarded as one unit:
Our team is winning.
Is plural when we mean each member of this unit individually:
The team are going back to their homes.