reminder
n. 提醒物，引起回忆的事物；（提醒做某事的）提示信，通知单
例句
This has been a timely reminder to us all.
对我们大家来说这个提醒非常及时。
《牛津词典》
His words were a pointed reminder of her position.
他刻意提醒了她的身份。
The accident was a salutary reminder of the dangers of climbing.
这次事故提醒人们注意登山的种种危险，倒也不无益处。
