anchor.diff:      **Do** declare components, directives, and pipes in a shared module when those 
       items will be re-used and referenced by the components declared in other feature modules.
       
  -    **坚持**在共享模块中声明那些可能被那些特性模块引用的可复用组件、指令和管道。
  +    **坚持**在共享模块中声明那些可能被特性模块引用的可复用组件、指令和管道。
   
   .s-rule.consider
     :marked
  
positive.code:   <a href="https://wikipedia.org/wiki/Single_responsibility_principle" target="_blank"><i>single responsibility principle</i> (SRP)</a>
    to all components, services, and other symbols. 
    This helps make the app cleaner, easier to read and maintain, and more testable.
  
    ### <a id="01-01"></a>Rule of One
    
  
negative.code:   :marked
      **Do** give components an _element_ selector, as opposed to _attribute_ or _class_ selectors.
  
      **坚持**给组建一个*元素*选择器，而不是*属性*或*类*选择器。
  
  .s-why
    :marked
  