翻译了一点DI的内容

public/docs/ts/latest/guide/dependency-injection.jade

@@ -455,6 +455,7 @@ include ../_util-fns
   
   `HeroListComponent`应该从注入进来的`HeroService`获取英雄数据。
   遵照依赖注入模式的要求，组件必须在它的构造函数中请求这些服务，[就像我们以前解释过的那样](#ctor-injection)。
+  只是个小改动：
   
 // #enddocregion di-prepare-for-injection-1
 +makeTabs(
@@ -467,8 +468,11 @@ include ../_util-fns
 .l-sub-section
   :marked
     ### Focus on the constructor
+    ### 来看构造函数
 
     Adding a parameter to the constructor isn't all that's happening here.
+    
+    往构造函数中添加一个参数并不是这里所做的一切。
 
   +makeExample('dependency-injection/ts/app/heroes/hero-list.component.2.ts', 'ctor')(format=".")
 
@@ -476,19 +480,30 @@ include ../_util-fns
   :marked
     We're writing in TypeScript and have followed the parameter name with a type annotation, `:HeroService`.
     The class is also decorated with the `@Component` decorator (scroll up to confirm that fact).
+    
+    我们正在写TypeScript，并且在参数名后面带有一个类型注解：`:HeroService`。
+    这个类还有一个`@Component`的装饰器（往上翻翻就知道了）。
 
     When the TypeScript compiler evaluates this class, it sees the `@Component` decorator and adds class metadata
     into the generated JavaScript code. Within that metadata lurks the information that
     associates the `heroService` parameter with the `HeroService` class.
+    
+    当TypeScript编译器编译这个类时，它会看到`@Component`装饰器，并且把类的元数据添加到所生成的JavaScript代码中。
+    藏在元数据中的信息会把`heroService`参数和`HeroService`类关联在一起。
 
     That's how the Angular injector knows to inject an instance of the `HeroService` when it
     creates a new `HeroListComponent`.
+    
+    为什么Angular的注入器会知道当创建`HeroListComponent`时需要注入一个`HeroService`的实例？这就是原理。
 // #docregion di-create-injector-implicitly-1
 :marked
   <a id="di-metadata"></a>
   ### Creating the injector (implicitly)
+  ### 创建注入器（隐式的）
   When we introduced the idea of an injector above, we showed how to create
   an injector and use it to create a new `Car`.
+  
+  我们前面在引入注入器的概念时，曾展示过如何创建一个注入器。
 // #enddocregion di-create-injector-implicitly-1
 +makeExample('dependency-injection/ts/app/car/car-injector.ts','injector-create-and-call')(format=".")
 // #docregion di-create-injector-implicitly-2
@@ -499,28 +514,46 @@ include ../_util-fns
   when it creates components for us &mdash; whether through HTML markup, as in `<hero-list></hero-list>`,
   or after navigating to a component with the [router](./router.html).
   If we let Angular do its job, we'll enjoy the benefits of automated dependency injection.
+  
+  但无论在《英雄指南》还是其它范例中，我们都没有发现这样的代码。
+  在必要时，我们 *可以* 写[使用显式注入器的代码](#explicit-injector)，但却很少这样做。
+  当Angular为我们创建组件时 —— 无论通过像`<hero-list></hero-list>`这样的HTML标签还是通过[路由](./router.html)导航到组件 —— 它都会自己管理好注入器的创建和调用。
+  只要让Angular做好它自己的工作，我们就能安心享受自动依赖注入带来的好处。
 // #enddocregion di-create-injector-implicitly-2
 // #docregion di-singleton-services
 :marked
   ### Singleton services
+  ### 单例服务
   Dependencies are singletons within the scope of an injector.
   In our example, a single `HeroService` instance is shared among the
   `HeroesComponent` and its `HeroListComponent` children.
+  
+  在一个注入器的范围内，依赖都是单例的。
+  在我们这个例子中，一个单一的`HeroService`实例被`HeroesComponent`和它的子组件`HeroListComponent`共享。
 
   However, Angular DI is an hierarchical injection
   system, which means that nested injectors can create their own service instances.
   Learn more about that in the [Hierarchical Injectors](./hierarchical-dependency-injection.html) chapter.
+  
+  然而，Angular DI是一个分层的依赖注入系统，这意味着被嵌套的注入器可以创建它们自己的服务实例。
+  要了解更多知识，参见[分层注入器](./hierarchical-dependency-injection.html)一章。
 // #enddocregion di-singleton-services
 
 // Skip this for Dart, for now
 // #docregion di-testing-component-1
 :marked
   ### Testing the component
+  ### 测试组件
   We emphasized earlier that designing a class for dependency injection makes the class easier to test.
   Listing dependencies as constructor parameters may be all we need to test application parts effectively.
+  
+  我们前面强调过，设计一个适合依赖注入的类，可以让这个类更容易测试。
+  在构造函数的参数中列出依赖，就是当我们要对应用的一部分进行有效测试时所要做的一切了。
 
   For example, we can create a new `HeroListComponent` with a mock service that we can manipulate
   under test:
+  
+  比如，我们可以使用一个mock服务来创建新的`HeroListComponent`实例，以便我们可以在测试中操纵它：
 // #enddocregion di-testing-component-1
 +makeExample('dependency-injection/ts/app/test.component.ts', 'spec')(format='.')
 // #docregion di-testing-component-2

public/index.jade

@@ -41,7 +41,7 @@ div(class="home-rows")
     div(class="text-container")
       div(class="text-block promo-3-desc")
         h3(class="text-headline") Incredible Tooling
-        h3(class="text-headline") 好到离谱的工具
+        h3(class="text-headline") 美妙的工具
         p(class="text-body").
           Build features quickly with simple, declarative templates. Extend the template language with your own components and use a wide array of existing components.  Get immediate Angular-specific help and feedback with nearly every IDE and editor.  All this comes together so you can focus on building amazing apps rather than trying to make the code work.
         p(class="text-body").