In general, we use apostrophes to indicate possession or contracted forms.

  • Apostrophes for possessive forms of nouns

    The possessive form of a singular noun is marked by an apostrophe followed by s.

    Small_OK the manager’s report
    Small_OK the lecturer’s hypothesis

    This rule applies in most cases even with a name ending in –s.

    Small_OK the PAS’s response
    Small_OK Erasmus’s success

    If a plural noun already ends in –s, the apostrophe is used alone.

    Small_OK the students work (several students)
    Small_OK the teachers room (all the teachers)

    Note that the apostrophe is also used in expressions of time periods.

    Small_OK eight weeks time
    Small_OK two weeks leave

    Degree titles should be written with an apostrophe followed by s.

    Small_OK bachelor’s degree
    Small_OK master’s degree

    But note the exception: doctoral degree, not doctor’s degree.

    Do not use apostrophes to indicate a decade, a plural acronym or the plurals of figures.

    Cross the 1990’s
    Small_OK the 1990s
    Cross URL’s
    Small_OK URLs
    Cross 747’s
    Small_OK 747s
  • Apostrophes for contractions

    Use apostrophes for contractions (you’re for you are, don’t for do not, it’s for it is or it has) but note that contractions are far less common in formal texts than they are in informal writing.

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