Inseparably associated with the concept of teaching is the concept of purposes, goals, and objectives. To teach, one must teach something to someone . The teacher may plan to develop conditioned responses as in the case of an audio-linguist, or he may plan to promote understanding as in the case of a cognitive teacher. Once he sets up goals, he must begin to develop plans for achieving his desired aims. Planning assists him in selecting and arranging the most efficient sequence of learning activities for arriving at the stated goals. From the point of view of time, the teacher may ask himself how he can afford to prepare sufficiently. From the point of view of student achievement, the answer is that he cannot afford not to.