This is a very low level script based exercise. Every student gets a copy. The teacher folds the paper in half along the y axis. Then hands one to student 1 and one to student 2. Student 1 reads their part, and student 2 responds with one or the other of the supplied responses. Then student 1 does the same. When they are done, flip the page over and switch roles. Do it several times and repeat over several classes.