Each unit includes references to the digital content that complements and enhances
          
        
        
          
            the learning experience.
          
        
        
          This content, which makes up the
        
        
          
            digital portfolio
          
        
        
          , is also integrated within the digital,
        
        
          page-faithful version of the
        
        
          
            Dual Book
          
        
        
          , providing the necessary context for exploiting
        
        
          each resource.
        
        
          
            Multi-medium learning
          
        
        
          The
        
        
          
            digital content
          
        
        
          in each unit includes a
        
        
          
            variety of activities with specific learning
          
        
        
          
            purposes:
          
        
        
          •  TO AWAKEN STUDENTS’ INTEREST
        
        
          • TO SUPPORT UNDERSTANDING
        
        
          • TO EXPAND OR REFLECT ON WHAT STUDENTS LEARN
        
        
          •  TO REVIEW CONTENT