Unlock is a four-level academic skills course that combines thought-provoking video from Discovery Education with carefully scaffolded exercises and a fresh approach to critical thinking skills. Unlock Reading and Writing Skills Level 4 provides 60-90 hours of classroom material. The Student's eBook is interactive and includes all of the content from the printed Student's Book plus extra features such as embedded videos from Discovery Education . Access to the Online Workbook is provided via a code and webpage link. Critical Thinking sections give students frameworks to formulate their own opinions and express themselves effectively in the end-of-unit academic tasks. Unique research into common learner errors (using the Cambridge English Corpus) focuses the language used in Unlock on those areas learners find most challenging."