anchor.diff:          In Angular&nbsp;2, we use property binding; there is no built-in *href* directive.
           We place the element's `href` property in square brackets and set it to a quoted template expression.
   
  -        在Angular 2中，并没有内建的*href*指令，我们可以改用属性绑定。
  +        在Angular 2中，并没有内建的*href*指令，我们改用属性绑定。
           我们把元素的`href`属性放在方括号中，并把它设成一个引号中的模板表达式。
   
           For more information on property binding see [Template Syntax](../guide/template-syntax.html#property-binding).
  
positive.code: 
          For a list of DOM events, see: https://developer.mozilla.org/en-US/docs/Web/Events.
  
          要查看DOM事件的列表，请参见<https://developer.mozilla.org/en-US/docs/Web/Events>。
  
          For more information see [Template Syntax](../guide/template-syntax.html#event-binding).
  
  
negative.code:         The `*ngIf` directive in Angular&nbsp;2 works the same as the `ng-if` directive in Angular&nbsp;1,
          it removes or recreates a portion of the DOM based on an expression.
  
          Angular 2中的`*ngIf`指令与Angular 1中的`ng-if`指令一样，
          它根据表达式的值移除或重建DOM中的一部分。
  
          In this example, the `table` element is removed from the DOM unless the `movies` array has a length.
  