30秒英语怎么说

30 seconds in English is "thirty seconds." It comes from the number 30 and the unit of time "second," which comes from the Latin "secundus," meaning "following" or "next."
For example:
"Please wait thirty seconds before trying again." (请等待30秒后再试。)
"I can run a mile in under thirty seconds." (我能在不到30秒的时间里跑完一英里。)
"The commercial break is only thirty seconds long." (广告时间只有30秒钟。)