Thank you very much Nayan. Very clear.

Hi Nederbulan, The word "geen" is used to negate a noun that, if not negated, would be preceded by "een". Is dat een auto? - Nee, dat is geen auto. (Is that a car? - No, that is not a car.) The word "geen" can also negate nouns that aren't preceded by any article, like some nouns in the plural and uncountable nouns. Hebben jullie tafels? - Nee, we hebben geen tafels. Hebben jullie geld? - Nee, we hebben geen geld. (Do you have tables? - No, we don't have tables.) (Do you have money? - No, we don't have money.) The word "niet" is kind of used in all other situations. Ik rook niet. - I don't smoke. Je hebt hem niet gehoord. - You didn't hear him. hope this helps?