Schoenberg, Irene E. <br/><br/>
Focus on Grammar  A basic course for reference and practice 

 - 2 ed. 
 - Nueva York  Addison Wesley Longman  2000 
 - 455 p. 
 - Pearson education .
<br/><br/>The verb be: present and past  Putting it all together 
<br/><br/><label>ISBN: </label>0 201 34676 1 
<br/><br/><label>Subjects--Topical Terms: </label><br/>INGLÉS - TEXTO DE ENSEÑANZA
<br/><br/><label>Dewey Class. No.: </label>420.1  / SCH