He is conscientious and diligent, and is never idle.

他是个勤谨人，整天闲不住。

《新英汉大辞典》

We must now assemble a group of support service workers, who are ready to be unsung heroes and who are diligent, conscientious and devoted to their work.

现在一定要有一批人搞后勤工作。这些人要甘当无名英雄，勤勤恳恳，热心为大家服务。

youdao

I'm diligent and conscientious on my job, with a sprit of responsibility and ambition. I'm mild, unobtrusive, self-disciplined and confident in characteristics.

本人工作认真、负责一丝不苟、且具有很强的责任心和进取心。本人性格温和、谦虚、自律、自信。

youdao

The next year, Easycram.com would need to offer a new and improved service, one that makes it even easier and faster to cram better--inching up from the least-conscientious to the sporadically diligent tiers of the student population.

FORBES: Book Excerpt