they're = they are
their = possessive (it is their cat, it is their dog)
there = place (the cat sleeps there, the dog sleeps there)
example:
they're a figure skater, and their dog is sleeping right there.
your = possessive (your cat, your dog)
you're = you are
example:
you're a figure skater and you take care of your dog.
basic marks/symbols
, = comma
commas are used as buffers, such as this example. they indicate a pause.
' = apostrophe
apostrophes are used for contractions. a contraction is multiple words being turned into one word. you're is a contraction. they're is a contraction.
apostrophes are also used in instances that indicate ownership.
samantha's with the apostrophe indicates that samantha owns something. samanthas without the apostrophe indicates that there are multiple samanthas; that samantha has been turned into a plural.
apostrophes are not used for plurals. the plural of "weekday" is not "weekday's", but "weekdays". the former indicates that someone or something named weekday owns something, or that it is a contraction of "weekday is".
: = colon
the colon is used primarily to indicate lists, or to say "this is what i mean" "this is what i'm thinking of" "the following list is examples of" etc.
; = semi-colon
the semi-colon is not interchangeable with the colon. the semi-colon is not a decoration. it is not interchangeable with a hyphen or a dash. it is sometimes interchangeable with a full-stop or a comma, within the right circumstances.
semi-colons indicate a certain type of pause, one that is not the same as that indicated by a comma. sometimes, they separate different ideas within one sentence; they're useful within longer sentences, to ensure they are not as hard to read.
- = hyphen
the hyphen is not a dash. the hyphen is used to join words to indicate that they have a meaning together, like "state-of-the-art" or "blue-eyed". they are also used in written texts to separate words between lines, such as in novels. hyphens only separate words by syllable. for example, "some-where" not "som-ewhere", "testi-mony" not "testim-ony".
— = em dash
the em dash is perhaps the most versatile and common dash. it is used to indicate an interruption or abrupt stop in speech— it can sometimes be used more naturally, such as in this example. here are more examples:
"well, i— i was, i dunno i... i don't remember, he was telling me to—"
"my name's stephanie— some call me steph or stephie."
"she told me i had to— wait a minute, did you turn the oven off?"

