1. They noticed some change in the weather.
General question - Did they notice any change in the weather?
Disjunctive question - They noticed some change in the weather, didn't they?
Negative - They didn't notice any change in the weather.
2. I have promised good to the industrious students.
General question - Have I promised good to the industrious students?
Disjunctive question - I have promised good to the industrious students, haven't I?
Negative - I haven't promised good to the industrious students.
3. There is an invitation to the Exhibition on your desk.
General question - Is there an invitation to the Exhibition on your desk?
Disjunctive question - There is an invitation to the Exhibition on your desk, isn't there?
Negative - There is no invitation to the Exhibition on your desk. / There isn't any invitation to the Exhibition on your desk.
4. They will join their group in a moment.
General question - Will they join their group in a moment?
Disjunctive question - They will join their group in a moment, won't they?
Negative - They won't join their group in a moment.