There are 72 units and 8 appendices. Each unit consists of: 1. language presentation through: sample sentences to show the language forms in use; an explanation of the language forms; a description of the uses of these forms; 2. practice through: controlled exercises to develop an awareness of the language forms; guided exercises to practise expressing the range of meanings conveyed by these forms; a transfer activity which provides a framework for further free practice of the language presented in the unit; 3. answers to the controlled and guided exercises.