The rules
- A plural noun that owns nothing takes no apostrophe: the scientists measured the rocks.
- A singular noun shows ownership with ’s: the planet’s orbit.
- A plural noun ending in s shows ownership with an apostrophe after the s: the planets’ orbits.
- A plural that doesn’t end in s adds ’s: the children’s museum, the women’s team.
- Its, their and whose own; it’s, they’re and who’s mean “it is,” “they are” and “who is”; there points to a place: it’s spring, and the bird feeds its chick there.
- A name ending in s still adds ’s: Carl Linnaeus’s system.
- When two people share one thing, only the last name takes ’s; when each owns their own, both do: Orville and Wilbur Wright’s airplane, Newton’s and Leibniz’s notations.
This time: 0 right, 0 wrong