Follow the rules below for forming words to show more than one of the things named:
For most words, add s: books, guitars. Except when making a plural of single letter, do not add an apostrophe to words or numbers to make them plural.
Add s to compound words written as single words: cupfuls, handfuls. For compound words that use separate words or link the words with a hyphen, make the most significant word plural: assistant attorneys, attorneys general, daughters-in-law, deputy chiefs of staff.
Add s to figures: General Motors built the car in the 1940s. The Boeing Co. sold 12 more 767s.
Don't change the spelling of proper nouns when making them plural. Add es to most proper names ending in es or z: Gonzalezes, Jameses, Joneses, Parkses. Add s to other proper names, including most proper names ending in y even if preceded by a consonant: the Clintons, the Abernathys, not the Abernathies.
Add es to most words ending in ch, s, sh, ss, x and z: churches, buses, foxes, fuzzes, glasses.
Change is to es in words ending in is: parentheses, theses.
Add es to most words ending in o if a consonant precedes o: echoes, heroes. There are exceptions: pianos.
Words with Latin roots: Change us to i in words ending in us: alumnus, alumni. Change words ending in on to a: phenomenon, phenomena. Add s in most words ending in um: memorandums, referendums but not addenda, curricula, media.
Avoid using a possessive name as a plural: The free passes are available at four McDonald's restaurants. Not: The free passes are available at four McDonald's.
Do not use 's when writing about words as words: His speech had too many ifs, ands and buts.
To avoid confusion, add 's to single letters: Dot your i's. She earned two A's and three B's on her report card. Add s to multiple letters: He knows his ABCs. They have three color TVs.

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