Hi, Pieanne, The first two are easy. The same ideas presented for the affirmative forms I've got a book. / I have a book. apply to the negative forms I haven't got a book. / I don't have a book. The third is even easier.

The idiom is "have got" in both American and British English. It is a purely idiomatic alternate for "have" and is not much used except in the present tense. That is, "have got" is the present tense of this idiom, even though "get" is the present