Primary inflectional negation forms¶
Tense |
Modal auxiliary |
Non-modal auxiliary |
|---|---|---|
Preterite |
He couldn’t swim. |
They hadn’t finished. |
Present |
He can’t swim. |
They haven’t finished. |
Absolutely no lexical verbs have forms of this kind: *tookn’t, *taken’t, etc. These are not contractions:
No general rule of pronunciation would yield won’t from contracting will + not, can’t from can + not, shan’t from shall + not
Every auxiliary has a negative form, not every form has a corresponding negative. “amn’t” doesn’t occur, “mayn’t” dropped out of use, etc. If it is a contraction, then these and other would be possible
In subject–auxiliary inversion constructions, the n’t forms occur where auxiliary not is impossible:
Isn’t it ready?
Is not it ready?
Won’t I need the ticket?
Will not I need the ticket?
There are semantic differences. Can’t does not always have the same meaning as can with not following it:
The roof rack can not be attached (expresses an option, leave the roof rack if you want)
The roof rack can’t/cannot be attached (a complain, fitting is impossible)