The Electronic Exercise (TEE) is an experimental adaptive learning system which uses knowledge structures to apply an intelligent tutoring algorithm and especially the representation of its surmise relation via HASSE diagrams to navigate within the learning material, to visualize the learning progress and convey the structure itself to the learner. TEE is implemented via dynamic HTML and comes with an editor tool for the structure and the test exercises. Thus an author or teacher can build its own TEE system easily.