Where are you from, Marta? I ask because I need a clarification on this question:

8. Do you think ambiguity is characteristic element of English sense of humour?

Do you mean English as in English people from the U.K., English as in American English or, if you are in a country that does not have English as a primary language, English in general.

It is a common misconception, in non-English areas, that all English is the same.