"Write well" 的英文表达可以是 "write effectively" 或 "write proficiently"。这个短语的来源可能源于对写作能力的要求，即能够使用恰当的语言、语法和文体来传达思想。

下面是一些英文例句及其中文翻译：

"He writes effectively, making his points clear and concise." (他写得非常有效，使他的观点明确简洁。)
"She writes proficiently in both Engpsh and Spanish." (她英语和西班牙语都写得非常熟练。)
"It's important to write well in order to be taken seriously in the business world." (在商界中要被重视，写好是很重要的。)