anchor.diff:    But feel free to exploit the `nativeElement` when that seems easier or more clear than the abstraction.
   
     * 在缺乏浏览器时，`DebugElement.styles`提供对元素样式的访问。
  -  但是，请随便使用`nativeElement`，它可能更加容易、更加清晰。
  +  但是，请随意使用`nativeElement`，它可能更加容易、更加清晰。
   
     * Angular adds a directive to the injector of the element to which it is applied. 
     The test for the default color uses the injector of the 2nd `<h2>` to get its `HighlightDirective` instance
  
positive.code:   这种测试程序通常比较小、更易阅读、编写和维护。
  
    They don't
    
    它们不会：
  
    * import from the Angular test libraries
  
negative.code: 
    Testing applications with the help of the Angular testing utilities is the main focus of this chapter.
  
    使用Angular测试工具测试应用程序是本章的重点。
  
    However, it's often more productive to explore the inner logic of application classes
    with _isolated_  unit tests that don't depend upon Angular.
  