Unlock offers 56 hours of course material per Student’s Book, which is extendable to 90 hours with the Digital Classroom material, Digital Workbook and other additional activities in the Teacher’s Manual and Development Pack.Unlock is a paired-skills course with two separate Student’s Books per level. For levels 1–5 (CEFR A1 – C1), these are Reading, Writing and Critical Thinking and Listening, Speaking and Critical Thinking. They share the same unit topics so you have access to a wide range of material at each level.The up-to-date content is informed by our Cambridge Academic Corpus, a huge collection of academic written materials providing insights into the English language and how people use it. High-frequency words in the Cambridge Academic Corpus are highlighted throughout.