meticulous

He devoted many hours of meticulous preparation for his final engineering project.

(Chinese) 他花了许多小时为他的最终工程项目做极其细致的准备。

The museum conservator used a tiny brush for the meticulous cleaning of the ancient oil painting.

(Chinese) 博物馆修复师用一把小刷子对那幅古老油画进行精细的清洗。