anchor.diff:    `@angular/core`库是主要的Angular模块库，从这里能获得大部分需要的东西。
     
     <br clear="all">
  -  
     There are other important Angular libraries too, such as `!{_at_angular}/common`, `!{_at_angular}/router`, and `!{_at_angular}/animate`.
     We import what we need from an Angular !{_library_module}.
     
  
positive.code:  
    * we register *providers* with injectors.
    
    * 把*提供商*注册到注入器。
  
    * The *injector* is the main mechanism.
      * An injector maintains a *container* of service instances that it created.
      * An injector can create a new service instance from a *provider*.
  
    * A *provider* is a recipe for creating a service.
  
    * We register *providers* with injectors.
  
  .l-main-section
  :marked
  
negative.code:   
    1. [Modules](#modules) 
    
    1. [模块(Modules)](#modules)
    
    1. [Components](#components)
    
    1. [组件(Components)](#components)
    
    1. [Templates](#templates)
    
    1. [模板(Templates)](#templates)
    
    1. [Metadata](#metadata)
    
  