• By adding –s to nouns ending in –f or –fe
• By adding –s if there is a vowel before the -y

Singular	Plural		Singular	Plural
beef	beeves		loaf	loaves
calf	calves		self	selves
half	halves		sheaf	sheaves
housewife	housewives		shelf	shelves
knife	knives		thief	thieves
leaf	leaves		wife	wives
life	lives		wolf	wolves

• By adding –s to nouns ending in –f or –fe
• By adding –s if there is a vowel before the -y