the AngularPlayList example error

[anjone]

Hi, when I run the AngularPlayList example,get these errors

zone.js:461 Unhandled Promise rejection: Template parse errors:
Can't bind to 'ngModel' since it isn't a known property of 'input'. ("
required
placeholder="title"
[ERROR ->][(ngModel)]="video.title"
>

"): VideoDetailComponent@14:20
Can't bind to 'ngModel' since it isn't a known property of 'input'. ("
required
placeholder="url"
[ERROR ->][(ngModel)]="video.url"
>

"): VideoDetailComponent@23:20
Can't bind to 'ngModel' since it isn't a known property of 'textarea'. ("

<textarea class="form-control" rows="5" [ERROR ->][(ngModel)]="video.desc">

        </textarea>

"): VideoDetailComponent@27:52 ; Zone: ; Task: Promise.then ; Value: BaseException {message: "Template parse errors:↵Can't bind to 'ngModel' sin… </textarea>
↵"): VideoDetailComponent@27:52", stack: "Error: Template parse errors:↵Can't bind to 'ngMod….1:8080/node_modules/zone.js/dist/zone.js:356:38)"}message: "Template parse errors:↵Can't bind to 'ngModel' since it isn't a known property of 'input'. ("↵ required
↵ placeholder="title"
↵ [ERROR ->][(ngModel)]="video.title"
↵ >
↵

↵"): VideoDetailComponent@14:20↵Can't bind to 'ngModel' since it isn't a known property of 'input'. ("↵ required
↵ placeholder="url"
↵ [ERROR ->][(ngModel)]="video.url"
↵ >
↵
↵"): VideoDetailComponent@23:20↵Can't bind to 'ngModel' since it isn't a known property of 'textarea'. ("
↵

↵ <textarea class="form-control" rows="5" [ERROR ->][(ngModel)]="video.desc">
↵
↵ </textarea>
↵"): VideoDetailComponent@27:52"stack: "Error: Template parse errors:↵Can't bind to 'ngModel' since it isn't a known property of 'input'. ("↵ required
↵ placeholder="title"
↵ [ERROR ->][(ngModel)]="video.title"
↵ >
↵

↵"): VideoDetailComponent@14:20↵Can't bind to 'ngModel' since it isn't a known property of 'input'. ("↵ required
↵ placeholder="url"
↵ [ERROR ->][(ngModel)]="video.url"
↵ >
↵
↵"): VideoDetailComponent@23:20↵Can't bind to 'ngModel' since it isn't a known property of 'textarea'. ("
↵

↵ <textarea class="form-control" rows="5" [ERROR ->][(ngModel)]="video.desc">
↵
↵ </textarea>
↵"): VideoDetailComponent@27:52↵ at new BaseException (http://127.0.0.1:8080/node_modules/@angular/compiler/src/facade/exceptions.js:27:23)↵ at TemplateParser.parse (http://127.0.0.1:8080/node_modules/@angular/compiler/src/template_parser/template_parser.js:98:19)↵ at RuntimeCompiler.compileTemplate (http://127.0.0.1:8080/node_modules/@angular/compiler/src/runtime_compiler.js:246:51)↵ at eval (http://127.0.0.1:8080/node_modules/@angular/compiler/src/runtime_compiler.js:174:83)↵ at Set.forEach (native)↵ at compile (http://127.0.0.1:8080/node_modules/@angular/compiler/src/runtime_compiler.js:174:47)↵ at ZoneDelegate.invoke (http://127.0.0.1:8080/node_modules/zone.js/dist/zone.js:323:29)↵ at Zone.run (http://127.0.0.1:8080/node_modules/zone.js/dist/zone.js:216:44)↵ at http://127.0.0.1:8080/node_modules/zone.js/dist/zone.js:571:58↵ at ZoneDelegate.invokeTask (http://127.0.0.1:8080/node_modules/zone.js/dist/zone.js:356:38)"__proto_: ErrorconsoleError @ zone.js:461_loop_1 @ zone.js:490drainMicroTaskQueue @ zone.js:494ZoneTask.invoke @ zone.js:426
zone.js:463 Error: Uncaught (in promise): Template parse errors:(…)consoleError @ zone.js:463_loop_1 @ zone.js:490drainMicroTaskQueue @ zone.js:494ZoneTask.invoke @ zone.js:426