1、英语a.m和p.m都是英语中的拉丁语。
2、Am ante meridiem表示正午前.0:00~12:00。
3、Pm post meridiem表示正午后 12：00～24：00。
拓展资料
a.m
1. His workday starts at 3.30 a.m. and lasts 12 hours.
他凌晨3点半开始工作，一直持续12小时。
2. A. M. Babu is a commentator on African affairs. A. M.
巴布是一位非洲事务评论员。
3. Eve, squinting at the clock, saw it was just on 7 a.m.
伊夫眯着眼瞥了一下钟，看到差不多是早上7点钟。
4. The Visitor Centre is open daily 8.30 a.m. – 4.30 p.m.
游客中心每日上午8：30至下午4：30开放。
5. Everyone had already assembled in the boardroom for the 9:00 a.m. session.
所有人都已集中到了董事会会议室，准备参加上午9点钟的会议。
6. The program starts at 9 a.m.
节目上午9点开始。
7. The clock had stopped at 2.12 a.m.
钟在凌晨2点12分时停了。
8. Sometimes I'd even call up at 4 a.m.
有时我甚至早上四点都打电话。
p.m
1. At approxi-mately 11:30 p.m., Pollard finally gave his consent to the search.
大概晚上11点半的时候，波拉德最终同意进行搜查。
2. At about 4.30 p.m. Audrey arrived at the office.
大约下午4点30分，奥德丽到了办公室。
3. By Friday at 5:30 p.m., I still hadn't heard from Lund.
直到周五下午5点半，我仍未收到伦德的消息。
4. The Visitor Centre is open daily 8.30 a.m. – 4.30 p.m.
游客中心每日上午8：30至下午4：30开放。
5. At six p.m. large groups poured from the numerous offices.
下午6点钟大群大群的人从无数办公楼里蜂拥而出。
6. The meeting began at precisely 4.00 p.m.
会议于下午4点整开始。