Closed questions
invoke relatively low-order thinking, often simple recall. Indeed,
a closed question may elicit no response at all (for example,
because the learner is worried about being wrong), and the
teacher may end up answering his or her own question! In
theory, open questions are more likely to promote deeper thinking,
but if they are too broad they may be equally ineffective.
The purpose of clarifying and probing questions is self-evident
(Box 8.5).