diff --git a/aio/content/translations/cn/api-plan.md b/aio/content/translations/cn/api-plan.md
index ef292876dc..4e05cfc671 100644
--- a/aio/content/translations/cn/api-plan.md
+++ b/aio/content/translations/cn/api-plan.md
@@ -2,104 +2,104 @@
 
 按照下列优先级进行翻译：
 
-状态|URL|浏览量|占比
----|---|---|----
-[x] |common/http/HttpClient | 7,263 | 2.26
-[x] |common/NgForOf | 6,281 | 1.95
-[x] |forms/NgModel | 5,648 | 1.75
-[x] |core/Component | 5,582 | 1.73
-[x] |common/NgIf | 4,940 | 1.53
-[x] |core/NgModule | 4,097 | 1.27
-[x] |router/Router | 4,049 | 1.26
-[ ] |animations/animate | 3,817 | 1.19
-[x] |common/NgClass | 3,715 | 1.15
-[x] |common/DatePipe | 3,576 | 1.11
-[x] |forms/FormsModule | 3,381 | 1.05
-[x] |core/Input | 3,354 | 1.04
-[x] |core/EventEmitter | 3,202 | 0.99
-[x] |core/Injectable | 3,177 | 0.99
-[x] |forms/FormGroup | 3,096 | 0.96
-[x] |forms/FormControl | 3,034 | 0.94
-[x] |router/ActivatedRoute | 2,993 | 0.93
-[x] |forms/AbstractControl | 2,930 | 0.91
-[x] |router/RouterLink | 2,929 | 0.91
-[x] |core/ViewChild | 2,870 | 0.89
-[x] |core/Directive | 2,767 | 0.86
-[x] |router/Routes | 2,331 | 0.72
-[x] |router/RouterModule | 2,227 | 0.69
-[x] |router/Route | 2,223 | 0.69
-[x] |common/http/HttpClientModule | 2,167 | 0.67
-[x] |core/ElementRef | 2,163 | 0.67
-[ ] |core/OnInit | 2,136 | 0.66
-[ ] |common/UpperCasePipe | 2,078 | 0.65
-[ ] |common/NgStyle | 1,935 | 0.60
-[ ] |router/RouterOutlet | 1,908 | 0.59
-[ ] |forms/Validators | 1,900 | 0.59
-[ ] |common/http/HttpHeaders | 1,790 | 0.56
-[x] |core/Pipe | 1,673 | 0.52
-[ ] |common/NgSwitch | 1,670 | 0.52
-[ ] |forms/NgForm | 1,597 | 0.50
-[ ] |core/Renderer2 | 1,562 | 0.49
-[x] |core/HostListener | 1,501 | 0.47
-[ ] |common/AsyncPipe | 1,447 | 0.45
-[ ] |core/ViewContainerRef | 1,367 | 0.42
-[ ] |common/NgTemplateOutlet | 1,337 | 0.42
-[ ] |common/Location | 1,306 | 0.41
-[ ] |platform-browser/BrowserModule | 1,281 | 0.40
-[ ] |common/DecimalPipe | 1,275 | 0.40
-[ ] |common/CurrencyPipe | 1,260 | 0.39
-[ ] |router/RouterLinkActive | 1,231 | 0.38
-[ ] |core/TemplateRef | 1,212 | 0.38
-[ ] |forms/FormBuilder | 1,205 | 0.37
-[ ] |common/http/HttpParams | 1,131 | 0.35
-[ ] |core/OnChanges | 1,116 | 0.35
-[ ] |forms/FormControlName | 1,082 | 0.34
-[x] |core/Output | 1,067 | 0.33
-[ ] |common/http/HttpInterceptor | 968 | 0.30
-[ ] |common/http/HttpRequest | 925 | 0.29
-[ ] |router/CanActivate | 863 | 0.27
-[ ] |router | 848 | 0.26
-[ ] |animations/style | 804 | 0.25
-[ ] |common/SlicePipe | 799 | 0.25
-[ ] |router/Event | 796 | 0.25
-[ ] |common/JsonPipe | 793 | 0.25
-[x] |forms/FormArray | 792 | 0.25
-[ ] |common/CommonModule | 787 | 0.24
-[ ] |router/NavigationExtras | 776 | 0.24
-[x] |core/HostBinding | 732 | 0.23
-[x] |core/ContentChild | 719 | 0.22
-[x] |core/ViewChildren | 717 | 0.22
-[x] |common/http/HttpResponse | 714 | 0.22
-[x] |router/ActivatedRouteSnapshot | 700 | 0.22
-[ ] |common/http | 683 | 0.21
-[ ] |core/ChangeDetectorRef | 670 | 0.21
-[ ] |router/NavigationStart | 663 | 0.21
-[ ] |common/formatDate | 662 | 0.21
-[ ] |core/ComponentFactoryResolver | 638 | 0.20
-[ ] |forms/Form | 635 | 0.20
-[ ] |common/http/HttpErrorResponse | 629 | 0.20
-[ ] |core/QueryList | 620 | 0.19
-[ ] |forms | 618 | 0.19
-[ ] |animations/state | 598 | 0.19
-[ ] |common | 596 | 0.19
-[ ] |router/LoadChildren | 593 | 0.18
-[ ] |router/ParamMap | 588 | 0.18
-[ ] |animations/trigger | 584 | 0.18
-[ ] |router/RouterLinkWithHref | 584 | 0.18
-[ ] |core/AfterViewInit | 579 | 0.18
-[ ] |forms/ReactiveFormsModule | 576 | 0.18
-[ ] |common/http/HTTP_INTERCEPTORS | 574 | 0.18
-[ ] |platform-browser/DomSanitizer | 573 | 0.18
-[ ] |core/PipeTransform | 572 | 0.18
-[ ] |core/SimpleChange | 570 | 0.18
-[ ] |core/SimpleChanges | 568 | 0.18
-[ ] |forms/NgSelectOption | 560 | 0.17
-[ ] |common/PercentPipe | 557 | 0.17
-[ ] |forms/ValidatorFn | 557 | 0.17
-[ ] |http/RequestOptionsArgs | 551 | 0.17
-[ ] |animations/animation | 549 | 0.17
-[ ] |common/NgSwitchCase | 521 | 0.16
-[ ] |core/testing/async | 518 | 0.16
+状态|URL|占比
+---|---|----
+[x]  | common/http/HttpClient  | 2.26
+[x]  | common/NgForOf  | 1.95
+[x]  | forms/NgModel  | 1.75
+[x]  | core/Component  | 1.73
+[x]  | common/NgIf  | 1.53
+[x]  | core/NgModule  | 1.27
+[x]  | router/Router  | 1.26
+[ ]  | animations/animate  | 1.19
+[x]  | common/NgClass  | 1.15
+[x]  | common/DatePipe  | 1.11
+[x]  | forms/FormsModule  | 1.05
+[x]  | core/Input  | 1.04
+[x]  | core/EventEmitter  | 0.99
+[x]  | core/Injectable  | 0.99
+[x]  | forms/FormGroup  | 0.96
+[x]  | forms/FormControl  | 0.94
+[x]  | router/ActivatedRoute  | 0.93
+[x]  | forms/AbstractControl  | 0.91
+[x]  | router/RouterLink  | 0.91
+[x]  | core/ViewChild  | 0.89
+[x]  | core/Directive  | 0.86
+[x]  | router/Routes  | 0.72
+[x]  | router/RouterModule  | 0.69
+[x]  | router/Route  | 0.69
+[x]  | common/http/HttpClientModule  | 0.67
+[x]  | core/ElementRef  | 0.67
+[x]  | core/OnInit  | 0.66
+[ ]  | common/UpperCasePipe  | 0.65
+[ ]  | common/NgStyle  | 0.60
+[ ]  | router/RouterOutlet  | 0.59
+[ ]  | forms/Validators  | 0.59
+[ ]  | common/http/HttpHeaders  | 0.56
+[x]  | core/Pipe  | 0.52
+[ ]  | common/NgSwitch  | 0.52
+[ ]  | forms/NgForm  | 0.50
+[ ]  | core/Renderer2  | 0.49
+[x]  | core/HostListener  | 0.47
+[ ]  | common/AsyncPipe  | 0.45
+[ ]  | core/ViewContainerRef  | 0.42
+[ ]  | common/NgTemplateOutlet  | 0.42
+[ ]  | common/Location  | 0.41
+[ ]  | platform-browser/BrowserModule  | 0.40
+[ ]  | common/DecimalPipe  | 0.40
+[ ]  | common/CurrencyPipe  | 0.39
+[ ]  | router/RouterLinkActive  | 0.38
+[ ]  | core/TemplateRef  | 0.38
+[ ]  | forms/FormBuilder  | 0.37
+[ ]  | common/http/HttpParams  | 0.35
+[ ]  | core/OnChanges  | 0.35
+[ ]  | forms/FormControlName  | 0.34
+[x]  | core/Output  | 0.33
+[ ]  | common/http/HttpInterceptor  | 0.30
+[ ]  | common/http/HttpRequest  | 0.29
+[ ]  | router/CanActivate  | 0.27
+[ ]  | router  | 0.26
+[ ]  | animations/style  | 0.25
+[ ]  | common/SlicePipe  | 0.25
+[ ]  | router/Event  | 0.25
+[ ]  | common/JsonPipe  | 0.25
+[x]  | forms/FormArray  | 0.25
+[ ]  | common/CommonModule  | 0.24
+[ ]  | router/NavigationExtras  | 0.24
+[x]  | core/HostBinding  | 0.23
+[x]  | core/ContentChild  | 0.22
+[x]  | core/ViewChildren  | 0.22
+[x]  | common/http/HttpResponse  | 0.22
+[x]  | router/ActivatedRouteSnapshot  | 0.22
+[ ]  | common/http  | 0.21
+[ ]  | core/ChangeDetectorRef  | 0.21
+[ ]  | router/NavigationStart  | 0.21
+[ ]  | common/formatDate  | 0.21
+[ ]  | core/ComponentFactoryResolver  | 0.20
+[ ]  | forms/Form  | 0.20
+[ ]  | common/http/HttpErrorResponse  | 0.20
+[ ]  | core/QueryList  | 0.19
+[ ]  | forms  | 0.19
+[ ]  | animations/state  | 0.19
+[ ]  | common  | 0.19
+[ ]  | router/LoadChildren  | 0.18
+[ ]  | router/ParamMap  | 0.18
+[ ]  | animations/trigger  | 0.18
+[ ]  | router/RouterLinkWithHref  | 0.18
+[ ]  | core/AfterViewInit  | 0.18
+[ ]  | forms/ReactiveFormsModule  | 0.18
+[ ]  | common/http/HTTP_INTERCEPTORS  | 0.18
+[ ]  | platform-browser/DomSanitizer  | 0.18
+[ ]  | core/PipeTransform  | 0.18
+[ ]  | core/SimpleChange  | 0.18
+[ ]  | core/SimpleChanges  | 0.18
+[ ]  | forms/NgSelectOption  | 0.17
+[ ]  | common/PercentPipe  | 0.17
+[ ]  | forms/ValidatorFn  | 0.17
+[ ]  | http/RequestOptionsArgs  | 0.17
+[ ]  | animations/animation  | 0.17
+[ ]  | common/NgSwitchCase  | 0.16
+[ ]  | core/testing/async  | 0.16
 
 ## 翻译方式
 
diff --git a/packages/core/src/metadata/lifecycle_hooks.ts b/packages/core/src/metadata/lifecycle_hooks.ts
index 61ce3af80a..796712d173 100644
--- a/packages/core/src/metadata/lifecycle_hooks.ts
+++ b/packages/core/src/metadata/lifecycle_hooks.ts
@@ -51,13 +51,20 @@ export interface OnChanges {
  * all data-bound properties of a directive.
  * Define an `ngOnInit()` method to handle any additional initialization tasks.
  *
+ * 一个生命周期钩子，它会在 Angular 初始化完了该指令的所有数据绑定属性之后调用。
+ * 定义 `ngOnInit()` 方法可以处理所有附加的初始化任务。
+ *
  * @see `AfterContentInit`
  * @see [Lifecycle Hooks](guide/lifecycle-hooks#onchanges) guide
  *
+ * [生命周期钩子](guide/lifecycle-hooks#onchanges)
+ *
  * @usageNotes
  * The following snippet shows how a component can implement this interface to
  * define its own initialization method.
  *
+ * 下列片段展示了组件要如何实现此接口，以定义它自己的初始化方法。
+ *
  * {@example core/ts/metadata/lifecycle_hooks_spec.ts region='OnInit'}
  *
  *
@@ -69,6 +76,9 @@ export interface OnInit {
    * data-bound properties for the first time,
    * and before any of the view or content children have been checked.
    * It is invoked only once when the directive is instantiated.
+   *
+   * 它的调用时机在默认的变更检测器首次检查完该指令的所有数据绑定属性之后，任何子视图或投影内容检查完之前。
+   * 它会且只会在指令初始化时调用一次。
    */
   ngOnInit(): void;
 }