Buster,
As a general rule, when you get a question right, you get to ask one. So to ask another question, you'd need to get one right. But we try to keep it to 2-3 open questions at a time, and sometimes you can't ask one right away for whatever reason, so you can ask a question later, as long as there is only 1 or 2 open questions. You'll see a lot of the veterans here will pop in and ask a question when there aren't any open because we have a stack of virtual AAQ's. (Hey I just called myself a vet. I guess I have been around for 3 of the 5 threads now so I'm justified).