正式的

• official
• state
• formal
• true
• full-dress
• ceremonial
• proper
• plenary
• card-carrying
• regular

例句

1. 这样的便服不宜在正式的场合穿。
   Such casual dress would not be correct for a formal occasion.
2. 这一部分人已从正式的联盟中分裂出来了。
   The group have split away/off from the official union.
3. 我们被邀参加一次正式的午宴。
   We were invited to a formal luncheon.