Teach’ and ‘test’ are quite close together in a dictionary, but in testing we do different things from the things we do when we teach. This article assesses the concept of ‘backwash’ in language teaching, looks at the consequences of testing on teaching in a broad educational context, and suggests that ‘negative backwash’ makes good language teaching more difficult. The two processes of testing and teaching are considered to be necessary but distinct. A system is described for distinguishing between them which is then applied to developing classroom activities for examination preparation classes, to help teachers move from testing to teaching procedures.