The unit 4 Sustainable Development of English Language for second year Baccalaureate, intend to make 2nd year Bac students able to: learn and expand vocabulary about sustainable development, express cause and effect, read and take notes from a text, learn about the future perfect and its uses, write a formal letter, improve their Internet skills, read about sustainable development across the world and at the end of this unit they will learn how to produce a booklet.