anchor.diff:  :marked
     ## Keep the app transpiling and running
     
  -  ### 让应用代码保持转译和运行
  +  ## 让应用代码保持转译和运行
     
     Enter the following command in the terminal window:
   
  
positive.code:     :marked
        Read more about the `[class]` binding in the [Template Syntax](../guide/template-syntax.html#ngClass "Template syntax: NgClass") guide.
  
        关于属性绑定的更多信息，见[模板语法](../guide/template-syntax.html#property-binding)。
  
    :marked
      The final version of the `<li>` looks like this:
    +makeExample('toh-2/ts/src/app/app.component.1.html', 'class-selected-2', 'app.component.ts (styling each hero)')(format=".")
  
    :marked
  
negative.code:     所以我们要把`hero`属性**替换**成`selectedHero`属性。
  
    +makeExample('toh-2/ts/src/app/app.component.ts', 'selected-hero', 'src/app/app.component.ts (selectedHero)')
    
    :marked
      The hero names should all be unselected before the user picks a hero, so
      you won't initialize the `selectedHero` as you did with `hero`.
  