diff --git a/aio/content/translations/cn/api-plan.md b/aio/content/translations/cn/api-plan.md
index 1e5ff71cb2..b70734ed9b 100644
--- a/aio/content/translations/cn/api-plan.md
+++ b/aio/content/translations/cn/api-plan.md
@@ -33,7 +33,7 @@
 [x]  | core/OnInit  | 0.66
 [x]  | common/UpperCasePipe  | 0.65
 [x]  | common/NgStyle  | 0.60
-[ ]  | router/RouterOutlet  | 0.59
+[x]  | router/RouterOutlet  | 0.59
 [ ]  | forms/Validators  | 0.59
 [ ]  | common/http/HttpHeaders  | 0.56
 [x]  | core/Pipe  | 0.52
diff --git a/packages/router/src/directives/router_outlet.ts b/packages/router/src/directives/router_outlet.ts
index 77d6283fc8..3556211ffc 100644
--- a/packages/router/src/directives/router_outlet.ts
+++ b/packages/router/src/directives/router_outlet.ts
@@ -18,6 +18,8 @@ import {PRIMARY_OUTLET} from '../shared';
  *
  * Acts as a placeholder that Angular dynamically fills based on the current router state.
  *
+ * 一个占位符，Angular 会根据当前的路由器状态动态填充它。
+ *
  * ```
  * <router-outlet></router-outlet>
  * <router-outlet name='left'></router-outlet>
@@ -27,6 +29,8 @@ import {PRIMARY_OUTLET} from '../shared';
  * A router outlet will emit an activate event any time a new component is being instantiated,
  * and a deactivate event when it is being destroyed.
  *
+ * 每当新组件实例化之后，路由出口就会发出一个激活事件；在销毁时则发出取消激活的事件。
+ *
  * ```
  * <router-outlet
  *   (activate)='onActivate($event)'
@@ -93,6 +97,8 @@ export class RouterOutlet implements OnDestroy, OnInit {
 
   /**
    * Called when the `RouteReuseStrategy` instructs to detach the subtree
+   *
+   * 受 `RouteReuseStrategy` 的指示，从子树中分离开时调用
    */
   detach(): ComponentRef<any> {
     if (!this.activated) throw new Error('Outlet is not activated');
@@ -105,6 +111,8 @@ export class RouterOutlet implements OnDestroy, OnInit {
 
   /**
    * Called when the `RouteReuseStrategy` instructs to re-attach a previously detached subtree
+   *
+   * `RouteReuseStrategy` 的指示，把以前分离的子树重新附加回来时调用
    */
   attach(ref: ComponentRef<any>, activatedRoute: ActivatedRoute) {
     this.activated = ref;