adj. 不成文的；口头的；没有记录的
unwritten law[律]习惯法；[律]不成文法
1.Like most languages, Koro is unwritten and transmitted orally.
就像大部分语言一样，珂珞语没有书写文字，依靠口耳相传。
2.The trick was to know that his true nature lived, as perfect as an unwritten number, everywhere at once across space and time.
秘诀在于懂得自己的本性，尽善尽美得像一个没有写出来的数字，它超越时间和空间，无处不在。
3.In the volumes of black history, much remains unwritten.
在黑人的史册中，有很多篇章尚未书写。
4.But for brands, there's an art to using Twitter, and the most successful at it follow an unwritten set of rules.
但是对于品牌，使用Twitter是有艺术的，在Twitter上最成功的企业都遵循一系列不成文的规则。
5.Here's why: Valley culture has an unwritten rule that if you don't like a job, or if you think your company isn't going anywhere, you leave.
这就是为什么：硅谷文化有一个不成文的规矩，如果你不喜欢某个工作，或者你觉得公司没啥前途，你走人即可。
6.The later chapters in his life remained unwritten, leaving us with no detailed answer to the question Whatever happened to Donald?
他生命中后面的章节还没有写完，没给我们留下任何详细记述。那么后来唐纳德身上发生了什么？