Typescript 如何将可观察值传递给@Input() Angular 4

我是angular的新手，我有以下情况，我有一个服务和两个相互关联的组件.

• online-quote
• dynamic-form

online-quote组件在其ngOnInit()方法中调用服务getAnswers():Observable<AnswerBase<any>[]>，其结果被传递给组件dynamic-form.

为了说明这种情况，这是我的两个组件的代码:

网上报价.组成部分html:

 <div>
    <app-dynamic-form [answers]="(answers$ | async)"></app-dynamic-form>
</div>

网上报价.组成部分ts:

@Component({
  selector: 'app-online-quote',
  templateUrl: './online-quote.component.html',
  styleUrls: ['./online-quote.component.css'],
  providers:  [DynamicFormService]
})
export class OnlineQuoteComponent implements OnInit {

  public answers$: Observable<any[]>;

  constructor(private service: DynamicFormService) {

   }

  ngOnInit() {
    this.answers$=this.service.getAnswers("CAR00PR");
  }

}

动态形式.组成部分html:

<div *ngFor="let answer of answers">
 <app-question *ngIf="actualPage===1" [answer]="answer"></app-question>
</div>

动态形式.组成部分ts:

@Component({
  selector: 'app-dynamic-form',
  templateUrl: './dynamic-form.component.html',
  styleUrls: ['./dynamic-form.component.css'],
  providers: [ AnswerControlService ]
})
export class DynamicFormComponent implements OnInit {
  @Input() answers: AnswerBase<any>[];

  constructor(private qcs: AnswerControlService, private service: DynamicFormService) {  }

  ngOnInit() {

    this.form = this.qcs.toFormGroup(this.answers);

  }

我的问题是，如果服务getAnswers():Observable<AnswerBase<any>[]>的结果信息是可观察的，那么将信息从online-quote传递到dynamic-form的正确方式是什么.

我试过很多方法，但都不管用.我想找个人帮我.非常感谢你！