这个项目失败了，因为它是由一群外行管理的。

The project failed because it was managed by ___amateurs.

在他早期的绘画生涯中，他显然是个业余爱好者。

In his early days as a painter, he was clearly an ___amateur.

修理工作看起来太马虎了，肯定是外行干的。

The repair job looked so sloppy that it had to be the work of an ___amateur.