adj.非正式的，未经正式批准的，非官方的，非公事的，私事的，私人的

The unofficial estimate suggests that over 5,000 people attended the concert.
非官方的估计显示，有超过5,000人参加了音乐会。
He's the team's unofficial leader, always motivating his teammates.
他是球队非正式的领袖，总是在激励他的队友们。
The restaurant has an unofficial dress code; most people dress up for dinner.
这家餐厅有一个非官方的着装要求；大多数人晚餐时会盛装打扮。
The mayor's spokesperson gave an unofficial response to the media before the official statement.
在官方声明之前，市长的发言人向媒体提供了非官方的回应。
They organized an unofficial football match between the two rival schools.
他们组织了一场两所竞争对手学校之间的非官方足球比赛。
Her blog has become an unofficial guide for travelers visiting the city.
她的博客已成为游客参观这座城市的一个非官方指南。
The company holds an unofficial Christmas party every year for employees to relax.
公司每年都会举办一次非官方的圣诞派对，让员工放松一下。
The teacher shared some unofficial tips with the students on how to ace the exam.
老师给学生们分享了一些非官方的技巧，教他们如何在考试中取得高分。
The group of friends established an unofficial book club to discuss their favorite reads.
这群朋友成立了一个非官方的读书俱乐部，用来讨论他们最喜欢的作品。
Despite not being elected, she became the neighborhood's unofficial representative.
尽管没有被选举，她却成为了社区的非官方代表。