anchor.diff:    We slipped in something extra there at the end!  We defined a
     template reference variable, **`#heroForm`**, and initialized it with the value, "ngForm".
   
  -  上面代码的最后出现一些额外的东西！定义了一个模板引用变量**`#heroForm`**，并初始化为"ngForm"。
  +  上面代码的最后出现一些额外的东西！定义了模板引用变量**`#heroForm`**，并初始化为"ngForm"。
   
     The variable `heroForm` is now a reference to the `NgForm` directive that governs the form as a whole.
   
  
positive.code:   the `submitted` property is false until we submit the form,
    as this fragment from the `HeroFormComponent` reminds us:
  
    主表单从一开始就是可见的，因为`submitted`属性是false，直到我们提交了这个表单。
    来自`HeroFormComponent`的代码片段告诉了我们这一点：
  
  +makeExample('forms/ts/app/hero-form.component.ts', 'submitted')(format=".")
  
negative.code: 
    `app.component.ts` is the application's root component. It will host our new `HeroFormComponent`.
  
    `app.component.ts`是应用的根组件，`HeroFormComponent`将被放在其中。
  
    Replace the contents of the "QuickStart" version with the following:
  
  