The signs for "understand" and "don't understand" use the same movement, orientation, handshape, and location. To distinguish between the two, what expression should you use to indicate the difference? move your head clockwise for "don't understand" and move your head counterclockwise for "understand"
nod for "don't understand" and shake your head for "understand"
nod for "understand" and shake your head for "don't understand"
turn your head to the left for "understand" and turn your head to the right for "don't understand"