C7 Use apostrophes when needed.
Details	Incorrect Examples	Correct Examples
a) Use an apostrophe in a contraction.	Its, ill, cant, were, or wont.	it’s, I’ll, can’t, we’re, or won’t.
b) When a noun is single, show possession by adding an apostrophe and S.	A ducks bill A dogs collar	A duck’s bill A dog’s collar
c) When a noun is plural, show possession by adding an apostrophe after the S  – but only if plural is made in the usual way, by adding S.	Two dogs collars Two dog’s collars	Two dogs’ collars
d) If the noun is plural but it is made in some unusual way, just add an apostrophe and an S.
Examples of nouns made plural in an unusual way would include those made in the Latin way: octopi, cacti, and data;	Cactuses’ Cactis’	cacti’s
those made in the German way: men, women, and children, oxen;	mens mens’	men’s
and those that just don’t change at all: sheep and deer.	sheeps sheeps’	sheep’s