Angular 官方教程：英雄指南 下载运行不了

1、报错信息：

D:\eclipse-workspace\dqgy\dqgy\toh-pt6>ng test
Could not find module "@angular-devkit/build-angular" from "D:\\eclipse-workspace\\dqgy\\dqgy\\toh-pt6".
Error: Could not find module "@angular-devkit/build-angular" from "D:\\eclipse-workspace\\dqgy\\dqgy\\toh-pt6".
    at Object.resolve (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\@angular-devkit\core\node\resolve.js:141:11)
    at Observable.rxjs_1.Observable [as _subscribe] (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\@angular-devkit\architect\src\architect.js:132:40)
    at Observable._trySubscribe (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\Observable.js:43:25)
    at Observable.subscribe (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\Observable.js:29:22)
    at DoOperator.call (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\operators\tap.js:29:23)
    at Observable.subscribe (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\Observable.js:24:22)
    at C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\util\subscribeTo.js:22:31
    at Object.subscribeToResult (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\util\subscribeToResult.js:7:45)
    at MergeMapSubscriber._innerSub (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\operators\mergeMap.js:75:38)
    at MergeMapSubscriber._tryNext (C:\Users\lenovo\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\operators\mergeMap.js:72:14)

解决办法：npm i --save-dev @angular-devkit/build-angular

2、报错信息：You seem to not be depending on "@angular/core" and/or "rxjs". This is an error.

解决办法：npm install