Nouns

Level B2–C2 · singular, plural & irregular forms

◎What you'll master

Spell regular plurals: +s, +es after -s/-sh/-ch/-x/-o, and consonant+y → ies.
Turn -f / -fe into -ves (leaf → leaves) — and know the exceptions (roof → roofs).
Use the common irregular plurals (child → children, foot → feet, person → people).
Handle academic Latin/Greek plurals (analysis → analyses, criterion → criteria, datum → data).
Give plural-only nouns (scissors, trousers, glasses) a plural verb.

1Regular plurals: the spelling rules

Most nouns just add -s. But the ending of the singular decides the exact spelling, and TOEFL rewards getting it exactly right.

If the noun ends in…	Rule	Example
most sounds	+ s	book → books, idea → ideas
-s, -ss, -sh, -ch, -x, -z	+ es	bus → buses, box → boxes, watch → watches
consonant + y	y → ies	city → cities, baby → babies
vowel + y	+ s (keep y)	key → keys, boy → boys
many nouns in -o	+ es	tomato → tomatoes, hero → heroes

⚠ Watch out — the -y rule depends on the letter before y: citys → cities, but keies → keys (a vowel comes before the y).

2-f / -fe → -ves (with exceptions)

Many nouns ending in -f or -fe change to -ves in the plural. The f sound softens to a v.

leaf → leaves · knife → knives · wife → wives · life → lives · shelf → shelves · half → halves · wolf → wolves · thief → thieves

But some just add -s

A group of common nouns keeps the f and simply adds -s.

roof → roofs · chief → chiefs · belief → beliefs · cliff → cliffs · proof → proofs

⚠ Watch out — three knifes → three knives, but two rooves → two roofs. Learn the -ves words as a set.

3Irregular & unchanging plurals

Some plurals change the whole word — no ending is added. These are high-frequency, so memorise them.

Singular	Plural
child	children
man / woman	men / women
foot / tooth	feet / teeth
mouse	mice
person	people

Unchanging plurals

A few nouns have the same form for singular and plural — only the verb or a number reveals which.

one sheep → three sheep · one fish → many fish · deer, species, aircraft, series stay the same

⚠ Watch out — never regularise these: two childs → two children; five sheeps → five sheep.

4Latin & Greek plurals in academic English

Academic and TOEFL texts are full of borrowed nouns that keep their original plural. Recognising them is essential for the Reading and Listening sections.

Singular	Plural	Field / use
analysis	analyses	research, statistics
thesis / crisis	theses / crises	academic writing
criterion	criteria	evaluation
phenomenon	phenomena	science
datum / index	data / indices	research, economics

One vs. many

The singular is one: one criterion, one phenomenon, one analysis. The plural is criteria, phenomena, analyses. In careful English, data and criteria take a plural verb: the data are conclusive.

⚠ Watch out — an important criteria → an important criterion (singular); this phenomena is → this phenomenon is.

5Plural-only nouns

Some everyday nouns for two-part objects exist only in the plural and take a plural verb. To count them, use a pair of.

scissors · trousers · jeans · glasses · shorts · pyjamas — The scissors are sharp. · My glasses are new.

These trousers are too long. / This trousers is too long.

⚠ Watch out — use a pair of to make them singular in agreement: A pair of scissors is on the desk.

6Quick reference: putting it together

Run any noun through this order — ending rule first, then check the exception lists you've memorised.

Type	Singular → Plural
+ es	church → churches, potato → potatoes
y → ies	country → countries
f → ves	wife → wives, shelf → shelves
irregular	tooth → teeth, person → people
academic	crisis → crises, criterion → criteria

Memory hook

If a word feels academic (ends in -is, -on, -um, -us), it probably has a Latin/Greek plural — pause and recall it rather than adding -s.

Practice — 15 questions with instant feedback

0 / 15 correct

Question 1

one box → two (plural)

Question 2

one baby → three ______

Question 3

one leaf → many (plural)

Question 4

one roof → two ______

Question 5

one child → five (plural)

Question 6

one tooth → all my ______

Question 7

one sheep → three (plural) in the field

Question 8

The study examined an unusual ______ of migration.

Question 9

one crisis → several (plural)

Question 10

The researchers applied three ______ to judge each essay.

Question 11

The (scissors) are on the desk.

Question 12

The ______ from three experiments were combined for the report.

Question 13

The librarian shelved the books on the (shelf → plural).

Question 14

Statistical ______ of the survey revealed two hidden patterns.

Question 15

Over the years, the two (woman → plural) became close friends and colleagues.

✎Fix the Error

Each sentence has one mistake in the underlined word. Type the correction and check.

1.She has two childs.

2.We need three knifes for the table.

3.The teacher gave us too many informations.

4.The datas show a clear trend.

5.In autumn the leafs turn brown.