anchor.diff:    
     The diagnostic *log to console* is just one more `then()` in the Promise chain.
   
  -  把诊断信息*记录到控制台*也只是在承诺的处理链中多了一个`then`而已。
  +  把诊断信息*记录到控制台*也只是在承诺的处理链中多了一个`then()`而已。
     
     You have to adjust the calling component to expect a `Promise` instead of an `Observable`:
   
  
positive.code: 
    Now that you know how the API works, implement `create()` as follows:
  
    现在，知道了这个 API 如何工作，我们就可以像这样实现`addHero()`了：
  
  +makeExample('server-communication/ts/src/app/toh/hero.service.ts', 'import-request-options', 'src/app/toh/hero.service.ts (additional imports)')(format=".")
  +makeExcerpt('src/app/toh/hero.service.ts', 'create')
  
  a#headers
  
negative.code:   You'll write a method for the `HeroListComponent` to call, a `create()` method, that takes
    just the name of a new hero and returns an `Observable` of `Hero`. It begins like this:
  
    我们将为`HeroListComponent`创建一个简单的`create()`方法，它将接受新英雄的名字，并且返回一个`Hero`型的`Observable`，代码如下：
  
  +makeExample('server-communication/ts/src/app/toh/hero.service.ts', 'create-sig')(format=".")
  
  