CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sao Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 2RU, UK www.cambridge,org Informationonthistitlewww.cambridge.org/9780521539111 c Cambridge University Press 1987, 1997, 2004 This publication is in copyright, Subject to statutory exception and to the provisions of relevant collective licensing agreement no reproduction of any part may take place without the written permission of Cambridge University Press First published 1987 Second edition 1997 Third edition 2004 Reprinted 2005 Printed in Dubai by Oriental Press ISBN-13978-0-521-53911-1Book ISBN-100521-539110Bo ISBN-13978-0-521-539128 Cassette Set BN-10 0-521-53912-9 Cassette Set ISBN-13 978-0-521-53913-5 Audio CD Set ISBN-100-521-53913-7 Audio CD Set