Quotation marks are also used for the titles of works that are parts of larger works. The larger work is underlined while the smaller work is set off in quotes. An apostrophe , ' unlike other marks of punctuation, does not separate words or divide words. The apostrophe is part of the word to show omission of one or more letters, indicates possession, or shows plural letters. There are two forms for omission of letters.
Contractions are the primary form for missing letters.
When the word shows possession. Mary 's hat was blown off her head by the wind. When the word does not end in an s, the apostrophe goes between the last letter of the word and the s. He collected two week s' of pay. When the word ends in an s, the apostrophe goes after the s.