Some students (even very good ones) seem so shy that they never hold up their hands when you ask a class question. If you call on this student and he/she doesn't know the answer, you risk turning them off for good. On the other hand, if they do supply an answer, you have created participation. One tactic (as mentioned in our lesson) would be to ask "opinion" type questions in this situation, since no right/wrong is involved. In my experience, however, shy students often answer "yes" or "no" or "not sure" to wiggle out of having to say something. Any other ideas?