How can students be taught crossfire skills?
Read James Copeland’s book Cross Examination in Debate, National Textbook Co.; read pages TA7 and TA8 of the NFL Manual; read John Munkman, The Technique of Advocacy, Butterworth (U.K.); read the Lost Art of Cross Examination by J. W. Ehrlich, Dorset Press; read The Art of Cross Examination by Francis L. Wellman, [check for used copies at abebooks.com. The Munkman is British so Amazon.com (U.K.) might be best]. Also, check your library.