Apostrophes and plurals | The Apostrophe | Punctuation | Khan Academy

How often should an apostrophe be used to form a plural in English?

• Frequently, for most words

• Only for proper nouns

• Almost never, except in very specific cases

• Only for numbers and dates

When is it appropriate to use an apostrophe to form a plural?

• When pluralizing a proper noun

• When pluralizing a lowercase letter

• When pluralizing an uppercase letter

• When pluralizing an acronym

When pluralizing an uppercase letter, like 'A's', should you use an apostrophe?

• Yes, always

• No, never

• Only if it's at the beginning of a sentence

• Only if it's a proper noun

How should you correctly pluralize acronyms such as CD, DVD, or MP3?

• CD's, DVD's, MP3's

• CDs, DVDs, MP3s

• CD'es, DVD'es, MP3'es

• CDs', DVDs', MP3s'