unwritten [ʌnˈrɪtn]

例句:

• They obey the one unwritten rule that binds them all—no talking.
  他们都遵守着那条约束他们所有人的默认规则——要守口如瓶。
  
• There is an unwritten Caste system with Ph.
  来自SA
• Removing the entitlements would be breaking an unwritten agreement.
  来自THETIMES
• an unwritten understanding that nobody leaves before five o'clock
  五点钟之前谁都不离开的默契
  
• They sinned against the unwritten rules of this meeting.
  他们违反了这次会议的不成文规定.
  
• Conforming to this unwritten and indeed unspoken rule.
  来自A. Brookner