Contractions use an apostrophe to indicate missing letters.
Contractions shorten words with an apostrophe to combine words in informal use.
Contractions should only be used in informal writing or in conversation/dialogue.
- present tense forms of “to be” and “to have”
- (am, is, are)
- (have, has)
- past tense of “to be” and “to have”
- (was, were)
- (had)
- does
- would (have)
- could (have)
- should (have)
- will
- shall
The past tense contractions for “to be” would be the same as the present tense. Context alone would identify the tense.
- I am >> I’m
- you are >> you’re
- he/she/it is >> he’s/she’s/it’s
- we are >> we’re
- you are >> you’re
- they are >> they’re
- I have >> I’ve
- you have >> you’ve
- he/she/it has >> he’s/she’s/it’s
- we have >> we’ve
- you have >> you’ve
- they have >> they’ve
will, shall >> apostrophe plus “-ll”
- they will, they shall >> they’ll
- same for the other subject pronouns
does >> apostrophe with “-s”
had, would, could, should >> apostrophe plus “-d”
- you had, you would >> you’d
- same for the other subject pronouns
would have, could have, should have >> apostrophe plus “-d” plus apostrophe plus “-ve”
- he would have >> he’d’ve
- same for the other subject pronouns
“Does” usually contract’s with a question word rather than a verb.
- Who’s he think he is?
- (Who does he think he is?)
- What’s she know?
- (What does she know?)
- When’s the show start?
- (When does the show start?)
- Where’s it happen?
- (Where does it happen?)
- Why’s he say that?
- (Why does he say that?)
- How’s he want to go?
- (How does he want to go?)
The contraction for negative “not” for informal speech is “n’t.”
Some verbs shorten their forms in the negative:
present and past forms of “to be”
- is not >> isn’t
- are not >> aren’t
- was not >> wasn’t
- were not >> weren’t
present and past forms of “to do”
- do not >> don’t
- does not >> doesn’t
- did not >> didn’t
present and past forms of “to have”
- have not >> haven’t
- has not >> hasn’t
- had not >> hadn’t
forms of “can” (as a helping verb)
- cannot >> can’t
- note that “cannot” loses an “n” when contracted
- could not >> couldn’t
- could not have >> couldn’t’ve
Others
- had not >> hadn’t
- might not >> mightn’t
- must not >> mustn’t
- ought not >> oughtn’t
- should not >> shouldn’t
- will not >> won’t
- would not >> wouldn’t
And more
- might not have >> mightn’t’ve
- must not have >> mustn’t’ve
- ought not have >> oughtn’t’ve
- should not have >> shouldn’t’ve
- will not have >> won’t’ve
- would not have >> wouldn’t’ve
English speakers often contract specific verbs with question words in conversation, making their use acceptable in dialogue.
with singular present forms of “to be” (“is”)
- who’s
- what’s
- when’s
- where’s
- why’s
- how’s
Examples:
- Who’s coming with us?
- What’s that on top of the car?
- When’s it gonna get down?
- Where’s the key?
- Why’s it not in the ash tray?
- How’s it gonna help if we can’t find the key?
with plural present forms of “to be” (“are”)
- who’re
- what’re
- when’re
- where’re
- why’re
- how’re
Examples:
- Who’re you with?
- What’re you doing?
- When’re you leaving?
- Where’re you going?
- Why’re you doing that?
- How’re you coming back?
with present forms of “to have”
Question word as singular subject
who’s, what’s, when’s, where’s, why’s, how’s
- Who’s got the keys?
- What’s been the plan?
- When’s he left?
- Where’s he gone?
- Why’s it all a secret?
- How’s she found out?
Question word as plural object
who’ve, what’ve, when’ve, where’ve, why’ve, how’ve
- Who’ve I kissed?
- What’ve you done?
- What’ve they wanted?
- When’ve we left?
- Where’ve you gone?
- Why’ve you missed the bus?
- How’ve they found what they’ve lost?
with present forms of “to do” using third person singular (“does”)
“Does” usually contract’s with a question word rather than a verb.
- Who’s he think he is?
- What’s she know?
- When’s the show start?
- Where’s it happen?
- Why’s he say that?
- How’s he want to go?
A few words use an apostrophe for an informal or slang use of the word, best used in dialogue, not in narrative.
Examples:
- ma’am (madam)
- o’ (of)
- ’em (them)
- y’ (you, as in “y’all”)
- e’er (ever, mostly in poetry)
- ‘n’ (and)
Wikipedia has an extensive list of contractions.