I AM CURIOUS ABOUT HOW YOU USE "CURIOUS"
Many Spanish people use the word "curious" incorrectly. For example they say: "It is very curious". They are, of course, translating directly from Spanish and the word "curioso". Instead of using the word "curious" it is better to use the word "interesting".
So the right phrase would be "Ahhh, that is very interesting". The word "curious" does exist in English but it is used in a different context. For example if you are interviewing someone and you want to know more information about them you might say: "I am curious about your professional experience, can you tell me more?"
Hope that helps.
Soy el director de Daniel Smith + Partners. Tengo más de 10 años de experiencia enseñando inglés a españoles.