anchor.diff:  :marked
     ### Appendix: Working with injectors directly
     ### 附录：直接使用注入器工作
  +  
     We rarely work directly with an injector.
     Here's an `InjectorComponent` that does.
     
     我们很少直接使用注入器工作。
  -  这里是一个`InjectorComponent`，它用到了。
  +  这里的`InjectorComponent`直接使用了注入器。
   // #enddocregion appendix-explicit-injector-1
   +makeExample('dependency-injection/ts/app/injector.component.ts', 'injector', 'app/injector.component.ts')
   // #docregion appendix-explicit-injector-2
  
positive.code:   the same mock data as before, but none of its consumers need to know that.
    
    我们的`HeroService`暴露了`getHeroes`方法，用于返回跟以前一样的模拟数据，但它的消费者不需要知道这一点。
  // #enddocregion di-4
  // #docregion di-5
  .l-sub-section
  
negative.code:   What matters is that the injector has a provider to go to when it needs a `Logger`.
    
    问题是：当注入器需要一个`Logger`时，它得先有一个供应商。
    
  // #enddocregion providers-2
  // #docregion providers-provide-1
  :marked
  