anchor.diff:    路由的配置可能迅速占领这个模块，并掩盖其主要目的，即为Angular编译器设置整个应用的关键配置。
   
     We should refactor the routing configuration into its own class.
  -  What kind of class?
  +  What kind of class? 
     The current `RouterModule.forRoot()` produces an Angular `ModuleWithProviders` which suggests that a
     class dedicated to routing should be some kind of module.
     It should be a [_Routing Module_](../guide/router.html#routing-module).
  
positive.code:    null,
    `app/app.module.ts (after), app/app.module.ts (before)`)
  :marked
    It's simpler and focused on indentifying the key pieces of the application.
  
    它更简单，专注于确定应用的关键部分。
  
  
negative.code:   当前的`RouterModule.forRoot()`产生一个Angular `ModuleWithProviders`，所以这个路由类应该是一种模块类。
    它应该是一个[**路由模块**](../guide/router.htm#routing-module)。
  
    By convention the name of a _Routing Module_ contains the word "Routing" and 
    aligns with the name of the module that declares the components navigated to".
  
    按约定，**路由模块**的名字应该包含“Routing”，并与导航到的组件所在的模块的名称看齐。
    
    Create an `app-routing.module.ts` file as a sibling to `app.module.ts`. Give it the following contents extracted from the `AppModule` class:
  
    在`app.module.ts`所在目录创建`app-routing.module.ts`文件。将下面从`AppModule`类提取出来的代码拷贝进去：
  