Here's an example for adding
an apostrophe to "students' responsibilities."
"Student's responsibilities" means that one student has many responsibilities.
"Students' responsibility" means that two or more students share one
"Students' responsibilities" means that two or more students
have many responsibilities.
Phrase a) is incorrect because
it contains no apostrophe to show possession.
Vera asks: Which of these phrases is correct?
a) students responsibilities
b) student´s responsibilities
Phrase (a) is not correct. It has no apostrophe,
and possessive forms of nouns must have an apostrophe, in both singular
Phrase (b) is not correct simply because it lacks an article before the
singular noun student. It would be correct if it were written
a student’s responsibilities (if the idea is any, indeterminate,
the student’s responsibilities (if the idea is one particular student,
or the generic "prototypical" student).
Phrase c) is correct. Plural possessives
have the apostrophe after the plural suffix, not before. Other such phrases
With irregular plurals, the apostrophe comes after the plural
form and before the "s":
women’s health care
In actual practice, we see a variety of deviations from
these principles, especially on signs in public localities. Still, standard
style requires that the apostrophe be placed after the plural