You probably need 'answers' to reference auth_user or come up with a scheme to track the person answering.
Then, select() a question and build a form. Perhaps:
question = db.question(1) #or however you want to pick the question
form = SQLFORM(db.answers)
form.vars.question_id = question.id
return dict(question=question, form=form)
To hide the form elements you don't want, you might need to either customize
the form or set readable/writable.
Q: {{=question.question}}<br>
A: {{=form}}
