Based on extensive research, Grammar and Beyond ensures that students study accurate information about grammar and apply it in their own speech and writing. In Workbook, Level 4, learners gain additional practice in the grammar from the Student's Book, including practice correcting common learner errors. Это и многое другое вы найдете в книге Grammar and Beyond 4 Workbook (Laurie Blass, Barbara Denman, Susan Iannuzzi)