New Interchange 3 Lab Cassettes are part of a lab program consisting of a Lab Guide and four hour-long Lab Cassettes. The program, designed to supplement each unit in the StudentŐs Book, gives students practice in listening comprehension, pronunciation, grammar, vocabulary, and oral fluency. The Lab Guide provides varying levels of support for the learner: Part A contains only the directions to each exercise, Part B contains the script for each exercise without the responses, and Part C contains the complete script for each exercise with the responses.