I am doing my homework now.
Negative. I'm not doing my homework now.
General q. Am I doing my home work now? Yes,I am. No, I am not.
Alternative q. Are you doing your homework or reading now?
Disjunctive q. I am doing my homework now, am I not?
Special q. Who is doing his homework now? What am I doing now?
His friends are having a dictation now.
Negative. His friends aren't having a dictation now.
General q. Are his friends having a disctation now? Yes, they are. No, they aren't.
Alternative q. Are his friends having a dictation or writing a test now?
Disjunctive q. Hiw friends are having a disctation now, aren't they?
Special q. Who is having a dictation now? What are his friends having now?