我不会再与他们合作了——他们完全是个外行。

I won't be working with them again - they are a complete ___amateur.

他承认自己技术不精，这就是项目失败的原因。

He admitted he was an ___amateur and that's why the project failed.

尽管他很热情，但他那业余的烹饪手法在最终菜品上显露无遗。

Despite his enthusiasm, his ___amateur approach to cooking was evident in the final dish.