anchor.diff:    (the `LoggerService`, `UserContext`, and the `UserService`)
     in the `@Component` metadata `providers` array.
     
  -  在下面的例子中，我们在`@Component`元数据的`供应商`数组中，导入和注册了几个服务（`LoggerService`, `UserContext`和`UserService`)。
  -
  +  在下面的例子中，在`@Component`元数据的`Providers`数组中，导入和注册了几个服务（`LoggerService`, `UserContext`和`UserService`)。
  + 
   +makeExample('cb-dependency-injection/ts/app/app.component.ts','import-services','app/app.component.ts (excerpt)')(format='.') 
   :marked
     All of these services are implemented as classes. 
     Service classes can act as their own providers which is why listing them in the `providers` array
     is all the registration we need.
     
  -  所有上面这些服务都是用类来实现的。服务类能充当它们自己的供应商，这就是为什么把它们列到一个`供应商`数组里是唯一的注册要求。
  +  所有上面这些服务都是用类来实现的。服务类能充当自己的供应商，这就是为什么把它们列到一个`providers`数组里是唯一的注册要求。
  +  
   .l-sub-section
     :marked
       A *provider* is something that can create or deliver a service.
       Angular creates a service instance from a class provider by "new-ing" it.
  -    Learn more about 供应商 [below](#providers).
  -    一个*供应商*是用来新建或者送交服务的。Angular从一个类供应商里面，通过“new-ing”来新建服务实例的。从[下面](#providers)学习更多关于provders的知识。
  +    Learn more about Providers [below](#providers).
  +    
  +    *供应商*是用来新建或者送交服务的。Angular从一个类-供应商里面，通过“new-ing”来新建服务实例的。从[下面](#providers)学习更多关于供应商的知识。
  +    
   :marked
     Now that we've registered these services,   
     Angular can inject them into the constructor of *any* component or service, *anywhere* in the application.
     
  -  现在我们已经注册了这些服务，Angular能在应用程序的*任何地方*，将它们注入到*任何*组件和服务的构造函数里面。
  +  现在已经注册了这些服务，Angular能够在应用程序的*任何地方*，将它们注入到*任何*组件和服务的构造函数里面。
  +  
   +makeExample('cb-dependency-injection/ts/app/hero-bios.component.ts','ctor','app/hero-bios.component.ts (component constructor injection)')(format='.') 
   
   +makeExample('cb-dependency-injection/ts/app/user-context.service.ts','ctor','app/user-context.service.ts (service constructor injection)')(format='.')    
  
positive.code:   We have to register our _own_ application providers manually, 
    usually in the `providers` array of the `Component` or `Directive` metadata:
    
    Angular初始化一些他自己建立和需要的注入器，附带一些供应商。我们必须要亲自手动注册属于_自己_的供应商，通常在`组件`或者`指令`的元数据里面的`供应商`数组（里面注册）。
  +makeExample('cb-dependency-injection/ts/app/app.component.ts','providers','app/app.component.ts (providers)') 
  :marked
    ### Defining providers
  
negative.code:   We could also provide the `HeroService` to a *different* component elsewhere in the application. 
    That would result in a *different* instance of the service, living in a *different* injector.
    
    我们也可以在应用程序的另外的地方的*不同的*组件里提供`HeroService`。这样的结果是该服务的*不同的*实例，在*不同的*注入器内存在。
    
  .l-sub-section
    :marked
      We examples of such scoped `HeroService` singletons appear throughout the accompanying sample code, 
      including the `HeroBiosComponent`, `HeroOfTheMonthComponent`, and `HeroesBaseComponent`. 
      Each of these components has its own `HeroService` instance managing its own independent collection of heroes.
      
      这个局限范围的`HeroService`单例的例子，贯穿伴随例子代码，包括`HeroBiosComponent`、`HeroOfTheMonthComponent`和`HeroBaseComponent`。
      这些组件中每个都有自己的`HeroService`实例，用来管理自己独立的英雄库。
  
  .l-main-section
  .alert.is-helpful
    :marked
      ### Take a break!
      ### 休息一下！
      
      This much Dependency Injection knowledge may be all that many Angular developers
      ever need to build their applications. It doesn't always have to be more complicated.
      
      对一些Angular开发者来说，这么多依赖注入知识可能是全部他们需要的知识。不一定都需要更加复杂的用法。
      
  <a id="multiple-service-instances"></a>
  .l-main-section
  