Gōng / chéng / shī / jīng / guò / duō / cì / cháng / shì / cuò / wù / zhōng / yú / gǎi / jìn / le / zhè / ge / shè / jì

工程师经过多次尝试错误，终于改进了这个设计。

After many rounds of trial and error, the engineer finally improved the design.