Teacher Collaboration: The Essential Common-Core Ingredient Phillips and Hughes explain Phillips and Hughes explain Phillips and Hughes explain Phillips and Hughes explain Phillips and Hughes explain Phillips and Hughes explain Teacher Collaboration: The Essential Common-Core Ingredient Teacher Collaboration: The Essential Common-Core Ingredient Phillips and Hughes explain Teacher Collaboration: The Essential Common-Core Ingredient Phillips and Hughes explain Phillips and Hughes explain Teacher Collaboration: The Essential Common-Core Ingredient Phillips and Hughes explain Teacher Collaboration: The Essential Common-Core Ingredient Teacher Collaboration: The Essential Common-Core Ingredient Teacher Collaboration: The Essential Common-Core Ingredient Teacher Collaboration: The Essential Common-Core Ingredient Teacher Collaboration: The Essential Common-Core Ingredient