anchor.diff:          
           我们通常会在一系列`gyp ERR!`消息后面看到一个`npm WARN`消息。直接忽略即可。
           有些依赖包可能会尝试用`node-gyp`重新编译它自己。
  -        如果重新编译失败了，这个包儿就会自行恢复（通常是下载一个预编译版本），最终不会影响使用。
  +        如果重新编译失败了，这个包就会自行恢复（通常是下载一个预编译版本），最终不会影响使用。
   
           Just make sure there are no `npm ERR!` messages at the end of `npm install`.
           
  
positive.code:     *Explanations* describe the concepts and reasons behind the instructions.
      Explanations have a thin border on the left like *this* block of text.
      
      *解释*，负责描述概念和操作指南背后的理由。解释在左侧有一个细边框，就像*这块儿文本*。
  
      Click *Hide Explanations* to show only the instructions.
      Click *View Explanations* to see everything again.
  
negative.code:       * `npm run tsc:w` - runs the TypeScript compiler in watch mode;
        the process keeps running, awaiting changes to TypeScript files and recompiling when it sees them
        
        * `npm run tsc:w` - 在“监视模式”下运行TypeScript编译器，进程持续运行，等待TypeScript文件的变化，一旦变化，就重新编译它们。
  
        * `npm run lite` - runs the <a href="https://www.npmjs.com/package/lite-server" target="_blank">lite-server</a>,
        a light-weight, static file server with excellent support for Angular apps that use routing
  