The Editor's Manual
Free learning resource on English grammar, punctuation, usage, and style.
Use parentheses (or round brackets) to set off supplementary information from surrounding text. Such information should not be essential to the grammar of the sentence. Periods go within parentheses if they belong to the parenthetical matter but outside otherwise.
Use masculine and feminine pronouns like “he” and “she” instead of “it” for animals with names or whose sex is known. To refer to a species or an animal whose sex is not known, use “it” instead.
Use “who” for animals with names, animals that are personified or anthropomorphized, or to indicate emotional closeness. Use “which” or “that” to discuss a species or an unknown animal without a name.
Use “who” as a relative pronoun to link a description to the person it describes. “Who” is used not just for people but also animals with names. “Who” can replace “whom” in informal usage.
Don’t use a comma before “who” when it presents information necessary to meaning (a restrictive clause). Do use a comma when “who” introduces an optional description (a nonrestrictive clause).
Use “each of” with singular verbs to refer to every one of a group separately. “Each of” may be followed by a plural, gender-neutral pronoun. In spoken English, “each of” is sometimes used with plural verbs to refer to an entire group.
When “each” is part of the subject of a sentence, it is used with singular verbs, except when it follows a plural noun. “Each” may be used with a plural pronoun in an indefinite reference.
Form the plural of a given or a family name by adding “s.” If the name ends in a sibilant sound (like “s,” “x,” “z”), add “es” instead.
Add “s” to form the plural of a name ending in a vowel. Don’t add “es,” even for names ending in “i” or “o.” Simply add “s” (“the Rossis,” not “Rossies”). Avoid using an apostrophe (“the Lees,” not “Lee’s”).
Form the plural of a name ending in “z,” “x,” “sh,” “s,” and other sibilant sounds by adding “-es” without an apostrophe (“the Diazes,” “the Hendrixes,” “the Williamses”).