1 alert /əˈlɚt/ adjective Learner's definition of ALERT
[more alert; most alert]
: able to think clearly and to notice things机敏的；机警的；警觉的 -
An alert guard stopped the robbers.机警的门卫拦住了劫匪。
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The nurse kept/stayed alert for any change [=watched for any change] in the patient's condition.护士对病人病情的任何变化时刻保持警觉。
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He was tired and had trouble staying alert while he was driving.他很疲倦，开车时无法保持警觉。
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She wasn't mentally alert enough to answer the questions.她头脑不够机敏，回答不了这些问题。
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an alert mind机敏的头脑
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An alert watchdog guarded the door.一只警觉的看门狗看守着大门。
—
often + to
— alertness
noun [noncount] 2 alert /əˈlɚt/ noun
plural alerts
plural alerts
Learner's definition of ALERT
1
[count] : something (such as a message or loud sound) that tells people there is some danger or problem : an alarm or signal of danger警告；警报；警示信号 -
They sounded an alert when enemy planes were approaching the city.敌机接近城市时，他们发出了警报信号。
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Medical officials have put out an alert to hospitals to look out for the virus.卫生官员已向各家医院发出警告，要小心这种病毒。
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The government has issued a terrorism/security alert.政府已发出恐怖袭击/安全警告。
2
[noncount] : the state of being ready for something you have been warned about (such as an attack)警戒；警惕；戒备—
used with on与On连用 -
We need to be on alert for any sudden changes.我们需要密切注意任何突发情况。
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The attack could come at any time, so the soldiers need to be on full alert.进攻随时都有可能发生，因此士兵需要时刻保持高度警惕。
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The recently flooded community is again on high alert as more rain is expected.预计更多的雨水将至，因此近期遭受洪涝灾害的地区再次处于高度戒备状态。
— see also red alert
on the alert
: looking for or expecting something (such as danger or an opportunity)警戒状态；密切注意着 —
often + for 3 alert /əˈlɚt/ verb
alerts; alerted; alerting
alerts; alerted; alerting
Learner's definition of ALERT
[+ object]
1
: to give (someone) important information about a possible problem, danger, etc. : to warn (someone)向…报警，使警觉；使警惕 -
Several neighbors alerted the authorities/police when they noticed strangers acting suspiciously.几个邻居注意到一些鬼鬼祟祟的陌生人，立即报告了当局/警方。
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The governor alerted island residents that a hurricane was coming.州长警告岛上居民飓风即将来临。
2
: to make (someone) aware of something提示，提醒（某人） —
often + to -
A friend recently alerted me to the existence of a new museum in my city.一个朋友最近提醒我说在我居住的城市有一座新的博物馆。
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We need to alert the public to the dangers of these chemicals. [=we need to tell the public about the dangers of these chemicals]我们需要提醒公众注意这些化学制品的危险性。