... Student'sBook ISB N-lO -S21-80S78-3 Student'sBook ISBN-13 978-0-S21-80S79-7 Teacher's Book ISBN-10 0-521-80579-1 Teacher's Book ISBN-13 978-0-521-80580-3 Workbook ISBN -lO 0-521-80580-5 Workbook ... Sharp for permission to reproduce their origi nal course book concept in Objective PET and in all other Objective examination course books The auth ors would like to thank Sue Ashcroft and Niki ... know any other punctuation marks? ~at!K What's the difference between the student's books and the students' books? you fat" YCXlr email mums cowrputer · ,s"t worl