anchor.diff:      We give both methods the same functional arguments. 
       
       唯一一个比较明显的不同点是我们调用这个返回的承诺的`then`方法，而不再是`subscribe`。
  -    而且我们给了这两个方法完全相同的调用参数。
  +    我们给了这两个方法完全相同的调用参数。
     .l-sub-section
       :marked
         The less obvious but critical difference is that these two methods return very different results!
  
positive.code:   
    Now that we know how the API works, we implement `addHero()`like this:
    
    现在，我们知道了这个API如何工作，就可以像这样实现`addHero()`了：
  
  +ifDocsFor('ts')
    +makeExample('server-communication/ts/app/toh/hero.service.ts', 'import-request-options', 'app/toh/hero.service.ts (additional imports)')(format=".")  
  
negative.code:   <a id="query-parameters"></a>
    :marked
      ### Search parameters
  
      ### 搜索参数
      
      The [Wikipedia 'opensearch' API](https://www.mediawiki.org/wiki/API:Opensearch)
      expects four parameters (key/value pairs) to arrive in the request URL's query string.
      The keys are `search`, `action`, `format`, and `callback`.
  