The difference between cannot and can not is confusing to a number of English language users. Despite that, there are simple rules to remember when you’re in a dilemma.
Both cannot and can not are acceptable but usually used differently.
cannot
cannot is an auxiliary verb that is much more usual as the opposite of can. When you describe an ‘impossible’ situation, use cannot. Its contraction is can’t.
Examples:
- I can do the dishes but he cannot.
- If I say I can, I will: if I say I cannot, I won’t.
can not
can not is usually used when it forms part of another body of words that starts with not. You should remember that can and not will always be separated if they belong to different but connected phrases within a sentence.
Examples:
- He can not only sing but play the piano.
Remember the above simple rules always and you’ll be fine.