• mark the end of a sentence (It is all over.)
• show contracted words (Prof., cont.) (Some countries use them for every contraction. Others only do so if the last letter of the contraction is not the last letter of the word e.g Mr. (US) but Mr (UK))
• are used in common abbreviations (e.g., i.e., etc.)
Apostrophes
• indicate possession (the boy’s book)
• indicate omitted letters or figures, including when showing accents (’tis, ’98, ’ere)
• indicate time or quantity (one week’s worth of chocolate)
• indicate plurals of letters or words (two F’s)
Commas
• show lists (whether or not including the Oxford comma) (apples, oranges and pears)
• join sentences with conjunctions (Harry went out, but it rained.)
• fill gaps (Harry had blue eyes; Sally, brown.)
• appear before/after direct speech (“It’s raining,” Harry said.)
• off-set interjection (Well, it was true.)
• bracket additional information (Harry wanted to go, regardless of the weather, but Sally said no.)
Colons
• introduce an additional part of the sentence that exemplifies, explains, or undermines what came before (There was only one thing Harry hated: getting wet.)
• start lists (usually these then have semi-colons instead of commas) (There were three things Harry hated about the winter: the rain; the cold; and the lack of sunlight.)
• set off subtitles (Jurassic World: Fallen Kingdom)
• precede dialogue in play/film scripts (Harry: Hang on a minute, Sally)
Semi-Colons
• separate two complete but related sentences where there is no conjunction and where a comma would create a splice (Sally bought an ice cream; she loved eating them whatever the weather.)
• separate list items introduced by a colon (see colon example above)