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Not vs Couldna - What's the difference?

not | couldna |

Couldna is a contraction of not.



As an adverb not

is negates the meaning of the modified verb.

As a conjunction not

is and not.

As an interjection not

is used to indicate that the previous phrase was meant sarcastically or ironically.

As a noun not

is unary logical function NOT, true if input is false, or a gate implementing that negation function.

As a contraction couldna is

contraction of could not have|lang=en.

not

English

(wikipedia not)

Adverb

(-)
  • Negates the meaning of the modified verb.
  • * 1973 , .
  • Well, I'm not a crook. I've earned everything I've got.
    Did you take out the trash? No, I did not .
    Not knowing any better, I went ahead.
  • To no degree
  • That is not red; it's orange.

    Usage notes

    In modern usage, the form do not ...'' (or ''don’t ...'') is preferred to ''... not'' for all but a short list of verbs (is/am/are/was/were, have/has/had, can/could, shall/should, will/would, may/might, need): * They do not''' sow.'' (modern) vs. ''They sow '''not . (KJB) American usage tends to prefer don’t have'' or ''haven’t got'' to ''have not'' or ''haven’t'', except when ''have'' is used as an auxiliary (or in the idiom ''have-not ): * I don’t have a clue'' or ''I haven’t got a clue. (US) * I haven’t a clue'' or ''I haven't got a clue. (outside US) * I haven’t been to Spain. (universal) The verb need is only directly negated when used as an auxiliary, and even this usage is rare in the US. * You don’t need to trouble yourself. (US) * You needn’t trouble yourself. (outside US) * I don’t need any eggs today. (universal) The verb dare can sometimes be directly negated. * I daren't do that.

    Conjunction

    (English Conjunctions)
  • And .
  • I wanted a plate of shrimp, not a bucket of chicken.
    He painted the car blue and black, not solid purple.

    Usage notes

    * The construction “A, not B” is synonymous with the constructions “A, and not B”; “not B, but A”; and “not B, but rather A”.

    Interjection

    not!
  • Used to indicate that the previous phrase was meant sarcastically or ironically.
  • I really like hanging out with my little brother watching ''Barney''... not !
    Sure, you're perfect the way you are... not !

    Synonyms

    * I don't think

    See also

    *

    Noun

    (en noun)
  • Unary logical function NOT, true if input is false, or a gate implementing that negation function.
  • You need a not there to conform with the negative logic of the memory chip.

    See also

    * AND * OR * NAND * XOR

    See also

    * if * then * else * and * or * true * false

    Statistics

    *

    couldna

    English

    Contraction

    (head)
  • (chiefly, slang)
  • You couldna said it better if you tried.