Guide to Grammar and Usage Singular child man foot tooth louse mouse Plural children men feet teeth lice mice 294 · Some nouns have the same form whether they are singular or plural. Singular swine series deer sheep moose species Plural swine series deer sheep moose species Possession Possession shows ownership. Follow these rules to create possessive nouns. · With singular nouns, add an apostrophe and s. Examples:girl, girl's manuscript; student, student's ideas · With plural nouns ending in s, add an apostrophe after the s.