你应该用你想要使用的组件创建一个共享模块，导出这些组件，并在你的其他模块中导入共享模块(你的父模块和子模块)案例).

You should create a shared module with the components you want to use, export these components, and import the shared module in your other modules (parent and child for your case).

共享模块:

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { SharedComponent1 } from "./SharedComponent1";
import { SharedComponent2 } from "./SharedComponent2";

@NgModule({
imports: [
    CommonModule
],
declarations: [
    SharedComponent1,
    SharedComponent2
],
exports: [
    SharedComponent1,
    SharedComponent2
]
})
export class SharedModule {}

使用共享模块:

import { NgModule }       from '@angular/core';
import { CommonModule }   from '@angular/common';
...
import { SharedModule } from './SharedModule';

@NgModule({
imports: [
    CommonModule,
    ...
    SharedModule
],
declarations: [
    ...
],
providers: [
    ...
]
})
export class AppModule{}