头头是道 well-reasoned
Explanation
原指佛家所说宇宙间一切事物都有其道理，后形容说话做事很有条理，合情合理。
Originally, it referred to the Buddhist teaching that everything in the universe has its own reason. Later, it was used to describe someone who speaks and acts very logically and systematically.
Origin Story
老李是一位经验丰富的木匠，他制作家具时总是头头是道。他先会仔细测量尺寸，然后绘制精准的图纸，每一个步骤都安排得井井有条，从选材到打磨，每一个环节都经过仔细的推敲和考量，最后制作出来的家具不仅美观大方，而且结实耐用。老李的儿子小明也喜欢木工，但做事总是毛手毛脚，没有计划，结果做的东西常常出现各种问题。老李便耐心地教导小明，告诉他做事要认真细致，要有计划，要一步一步地来，并且给他讲解制作家具的每一个步骤和技巧，最终小明也学会了像老李一样头头是道地制作家具。
Old Li was an experienced carpenter. When he made furniture, he always had a clear plan. First, he carefully measured the dimensions, then drew precise drawings, and every step was arranged in an orderly manner. From selecting materials to polishing, every link was carefully considered and reviewed. The furniture he made was not only beautiful and generous but also strong and durable. Li's son, Xiao Ming, also liked carpentry, but he was always clumsy and unplanned, resulting in various problems in his work. Li patiently taught Xiao Ming, telling him that work must be done carefully and with a plan, step by step. He explained every step and skill in making furniture, and finally, Xiao Ming also learned to make furniture as systematically as Old Li.
Usage
用于形容说话或做事条理清晰，合情合理。
Used to describe someone who speaks or acts clearly and logically.
Examples
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他的演讲头头是道，令人信服。
tā de yǎnjiǎng tóutóushìdào, lìng rén xìnfú
His speech was well-reasoned and convincing.
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这份计划书头头是道，非常周全。
zhè fèn jìhuà shū tóutóushìdào, fēicháng zhōuquán
This business plan is very comprehensive and thorough.