Topic · Plurals
One becomes many — six rules and a handful to memorise
Most plurals follow a rule (just add -s); a few change endings (-es, -ies, -ves); and a small set are completely irregular (mouse → mice) and must simply be learned. In Stage 1 you pick the one correct plural from five. Spot the ending of the singular word and the rule follows.
Rule 1 The default: just add -s
Most nouns simply add -s with no other change.
cat → cats · book → books · house → houses · tree → trees ✓
Rule 2 Hissing endings: add -es
If the word ends in s, ss, x, z, ch, sh, add -es (you can hear the extra syllable).
bus → buses · box → boxes · church → churches · dish → dishes · buzz → buzzes ✓
Listen test: if saying "-s" alone would be hard (boxs?), you need -es.
Rule 3 Ending in y
Consonant + y: change y → ies. Vowel + y: just add -s.
baby → babies · city → cities · lady → ladies (consonant + y) ✓
key → keys · day → days · boy → boys (vowel + y) ✓
Rule 4 Ending in f or fe
Often change f/fe → ves.
leaf → leaves · knife → knives · wolf → wolves · half → halves ✓
But some just add -s: roof → roofs, chief → chiefs, cliff → cliffs. These must be learned.
Rule 5 Ending in o
Some add -es, some add -s — there's no perfect rule, so learn the common ones.
potato → potatoes · tomato → tomatoes · hero → heroes (add -es) ✓
piano → pianos · photo → photos · zoo → zoos (add -s) ✓
Rule 6 Irregular plurals — memorise these
These don't follow any rule. Learn them by heart.
man → men · woman → women · child → children · person → people · tooth → teeth · foot → feet · mouse → mice · goose → geese ✓
No change at all: sheep → sheep, deer → deer, fish → fish, aircraft → aircraft.
The 30-second method
How to crack any plural MCQ fast
- Look at the last letters of the singular — that decides the rule.
- Hissing end (s/x/z/ch/sh)? → -es. Consonant + y? → -ies.
- Ends in f/fe? Try -ves first (leaves, knives), but watch the -s exceptions (roofs).
- Is it on the irregular list? (man, child, mouse, tooth…) — recall the special form.
- Reject the apostrophe. An apostrophe (cat's) is never a plural — that's a classic trap.
10 worked examples
Read the question, then the answer with the rule that solves it.
1. Plural of book?
books — default rule, just add -s (Rule 1).
2. Plural of box?
boxes — ends in x, so add -es (Rule 2).
3. Plural of baby?
babies — consonant + y becomes -ies (Rule 3).
4. Plural of key?
keys — vowel + y just adds -s (Rule 3).
5. Plural of knife?
knives — fe becomes -ves (Rule 4).
6. Plural of roof?
roofs — an exception that just adds -s (Rule 4 exception).
7. Plural of tomato?
tomatoes — this -o word takes -es (Rule 5).
8. Plural of child?
children — irregular; must be learned (Rule 6).
9. Plural of mouse?
mice — irregular; not "mouses" (Rule 6).
10. Plural of sheep?
sheep — no change at all (Rule 6).