can not/can't

[blouen]

I heard somebody say that I couldn't use can't/can not interchangeably at my own will. He said there are rules on when to use each.

I don't agree with him, and said that can't and cannot doesn't differ from each other in any way but is merely contracted. Thus, both words are one and the same, simply contracted for the ease of saying them.

I hope you can help me how to explain this.

[riverkid]

I heard somebody say that I couldn't use can't/can not interchangeably at my own will. He said there are rules on when to use each.

I don't agree with him, and said that can't and cannot doesn't differ from each other in any way but is merely contracted. Thus, both words are one and the same, simply contracted for the ease of saying them.

I hope you can help me how to explain this.

Not rules so much, B as reasons we use different structures/forms in different situations.

A simple example.

The normal neutral for speech are the contracted forms, it's; I won't; I can't; etc.

When we use full forms,

It is not; I will not; I can not,

our speech is more strident, angrier, less polite, not as neutral.

[blouen]

I see.
Putting some stress on the "not" makes us sound angrier...