1
be on alert for sth
The army is on alert for any possible attack.
军队对任何可能的袭击保持警觉。
警报；警告
alerts — plural of alert
先理解核心含义，再看它在真实句子里的用法。
警报；警告
A warning or alarm that tells people about danger.
The army is on alert for any possible attack.
军队对任何可能的袭击保持警觉。
警报。
An alarm.
高度警觉或准备行动的状态
condition of heightened watchfulness or preparation for action
一种重要性高于咨询的通知。
A notification of higher importance than an advisory.
警告使你对危险更加警觉
a warning serves to make you more alert to danger
The soldiers were placed on high alert after the suspicious activity was reported.
在报告可疑活动后，士兵们被置于高度戒备状态。
AI contextual example
The weather service issued a tornado alert for the entire region.
气象部门向整个地区发布了龙卷风警报。
AI contextual example
Residents remained on alert for further aftershocks following the earthquake.
地震后居民保持警惕，以防余震。
AI contextual example
bombers were put on alert during the crisis
在危机期间,轰炸机处于警戒状态
WordNet
The army is on alert for any possible attack.
军队对任何可能的袭击保持警觉。
也可用 send out an alert。
The government issued an alert about the approaching storm.
政府发布了关于即将到来的风暴的警报。
The siren sounded the alert to warn residents.
警报器拉响警报以警告居民。
Not this
The soldiers were in alert.
Use this
The soldiers were on alert.
表示‘处于警戒状态’时，固定搭配介词为on，而非in。应使用‘on alert’或‘on the alert’。
Not this
We received alert about the storm.
Use this
We received an alert about the storm.
alert作可数名词‘警报’时，单数形式前需加不定冠词a/an，表示‘一个警报’。
Choose the next layer that will help you use alerts with more confidence.
Missing: Antonyms
Complete this area with antonyms.
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
保持警惕；处于戒备状态
Police are on the alert for suspicious activity.
警方保持警惕，注意可疑活动。
发出警报
The system sounds an alert when the door is opened.
门被打开时，系统会发出警报。
发布警报；发出警告
The government issued an alert about the approaching storm.
政府发布了关于风暴来袭的警报。
红色警报；紧急戒备状态
The military was placed on red alert.
军方进入了红色警戒状态。
安全警报；安全警告
The airport was put on security alert after a suspicious package was found.
发现可疑包裹后，机场进入了安全警戒状态。
洪水警报
The river is rising, and the council has issued a flood alert.
河水上涨，市政委员会发布了洪水警报。
警惕着；戒备着
The guards were on the alert for any sign of movement.
警卫们警惕着任何动静。
红色警报；紧急戒备
The airport was put on red alert after the threat.
威胁发生后，机场进入红色警报状态。
高度戒备
Security forces remain on high alert along the border.
安全部队在边境保持高度戒备。
红色警报！——美国科幻剧《星际迷航》中舰长下令全员进入最高戒备状态时的著名口令。
The ship's computer sounded an alert the moment the enemy appeared on the radar.
敌舰出现在雷达上的那一刻，舰上的计算机就拉响了警报。
Use alerts naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
记忆联想：想象警报（alert）响起，你立刻绷紧神经、竖起耳朵准备行动——这就是 alert 的‘警觉/戒备’。
语域：mixed 常见场景：emergency warning systems、military or police readiness、mobile and software notifications alert 作名词时，可用于紧急警报、军事或警方戒备等较正式场合，也常见于手机和软件通知等日常场景。语气随语境不同，正式或中性，通常不是俚语或粗俗说法。
可数名词指具体的警告信号；不可数名词指保持警觉的状态
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY, WORDNET.