........................................(we have) an exam next week?

1. The sentence is a question about a future event.

2. The structure for 'be going to' questions is: Wh-word + am/is/are + subject + going to + verb? (Here, the 'Wh-word' is implied, and it's a yes/no question).

3. Therefore, the answer is: Are we going to have an exam next week?