Uses of ITS: Which Role for the Teacher?

We examine here the role of the context around the learner when using an ITS facing the problem of integration of ITS in their context of uses. Questions are raised which impose constraints during Sie design of ITS themselves. For example, if a teacher is available near die learner, which role for this teacher? What about the knowledge the system has of this role? If there is a group of learners and few teachers, which representation of the available possibilities to help the learner? How to share teacher’s time between different learners? What place for possibilities of experiments and hands-on work by learners in experimental sciences? How to take account of such possibilities? We describe some possible scenarios for use and explore some needs which are generally ignored when designing ITS.