I'd be happy to do it, but that is the context I'm looking for . I know that "not at all" can be used in contexts like these: not at all <-----Russian phrase removed by moderator (Florentia52)----->But I have a very vague idea of the contexts in which I could (or should) meet the first two. And maybe there are any other context for not at all similar to the none at all and nothing at all. They look very alike and confusing to me now.
The thing is they are frequently used in the tests I do as the diversion of the mind from the right answer (I know that from the key answers ). So the context is the problem.
The phrase at all simply intensifies the meaning of the word in front of it.
So you are asking for the meanings of none or nothing, both of which can stand alone.
For example: How many polar bears are there at the South Pole? Answer: None/None at all/Absolutely none.
The phrase not at all means no.
Are you angry? Answer: No/Not at all/Absolutely not.
You should not find it difficult to ask a question to which the answer is Nothing.
Thank you, e2efour. You've helped me a lot. I no longer perceive these phrases as idiomatic (except not at all) and now I see that the problem lay in the words no, not, nothing and none rather than in at all. I must confess I have some uncertainty about these words and your additional information proves that there is some complexity concerning them. But the good news is I know where to look now.