Valid period
[化] 有效期限\\n[经] 有效期限
🧩 词语组成解析
period
['pɪrɪəd]
n. 时期;（一段）时间;学时;句号;
adj. 具有某个时代特征的;（关于）过去某一特定历史时期的;（家具、服饰、建筑等）某一时代的;
peri周围，靠近+od道路→周期
🗣️ 情景例句
Nobody knows how to do it.
没有人会打。
I enjoyed the movie very much. I wish I had read the book from which it was made.
电影不错，我希望我读过原著。[wish + 主语 = 过去完成时 = 愿望之事在wish以前发生。]
some snakes manufacture a poison different in every respect from that of others,
有些蛇产生的毒液也在各方面与另外一些毒蛇产生的毒液不同，