The given sentence is: "First they have been shooting at each other for the last one hour."
The negative form of this sentence is: "For the last one hour, they haven't been shooting at each other."
The interrogative form of this sentence is: "For how long have they been shooting at each other?"
Original sentence:
First, they have been shooting at each other for the last one hour.
Negative forms:
They haven't been shooting at each other for the last one hour. (Simple negation)
It is not the case that they have been shooting at each other for the last one hour. (More complex negation)
Interrogative forms:
Have they been shooting at each other for the last one hour? (Yes/No question)
How long have they been shooting at each other? (Information-seeking question)
Have they really been shooting at each other for the last one hour? (Question expressing disbelief)
Is it true that they have been shooting at each other for the last one hour? (Question seeking confirmation)