A practical English Grammar is intended for intermediate  and post-intermediate students. We hope that more advanced learners and teachers will also find it useful. The book is a comprehensive survey of structures and forms, written in clear modern English and illustrated with numerous examples. Areas of particular difficulty have been given special attention. Differences between conversational usage and strict grammatical forms are shown but the emphasis is on controversial forms. In the fourth edition the main changes are as follows. 1. Explanation and examples have been brought up to date. 2. There is now more information on countable and uncountable nouns, attributive and predicative adjectives, adverbs of place, sentence adverbs, cleft sentences, prepositions, conjunctives, modal verbs, perfect tenses, infinitive constructions, the passive, purpose clauses and nouns. 3. Some material has been rearranged to make comparisons easier. For example, parts of chapters on can, may, must etc. are now grouped by functions; verbs of liking and preference have a chapter to themselves; suggestions and invitations have joined the chapter on commands, requests and advice. 4. The contents list now summaries every edition heading, and there is a new index containing many more entries references. In this edition the sign "~" is frequently used to show a change of speaker in examples of dialogue. Note also that although the sign "=""" sometimes connects two words or expressions with the same meaning, it is often used more freely, e.g. to indicate a transformation from active to passive or direct to indirect speech. We wish to thank all at Oxford University Press who have assisted in the preparation of the fourth edition. We would also like to thank Professor Egawa of Nihon University, Japan, Professor Rene Dirven of Duisburg University, West Germany and other colleagues for their friendly and helpful suggestions. London, November 1985   A.J.T., A.VM When you see this line in the book, "Did you get a ticket? ~Yes, I managed to get one", we can understand that  _  .
the two parts before and after the sign "~" mean the same the two parts before and after "~" are said by two different people the second speaker repeats what the first speaker says the topic is changed in the part after the sign "~"