alert
alert — adjective
1. paying close attention to what is happening around you, so that you can notice p
paying close attention to what is happening around you, so that you can notice problems or react quickly when something matters.
The lifeguard stayed alert as children splashed in the deep end of the pool.
stay alert (vigilant in a risky setting)
Drivers must be alert to cyclists when turning right at busy junctions.
alert to + noun for the danger you watch for
After two cups of coffee, Hana felt sharp and alert during the morning meeting.
Park rangers remain alert for signs of forest fires during the dry summer months.
Grandma is ninety, but her mind is still bright and alert.
- drowsy
physically sleepy, opposite of mentally awake
- inattentive
failing to notice what is happening around you
文法句型
alert to + noun
stay/remain/be alert
用法筆記
Often followed by 'to' (a danger) or 'for' (signs of something). Frequently appears in the linking pattern 'be / stay / remain alert', describing either physical watchfulness or mental sharpness.
常見錯誤
alert — noun
1. an official message that tells people about a danger or important event so that
an official message that tells people about a danger or important event so that they can prepare or take action.
The weather service issued a flood alert for villages along the river yesterday evening.
issue + alert (official sender)
Imani's phone buzzed with an earthquake alert just seconds before the shaking began.
modern collocation: phone + alert
Police sent out a public alert after the small girl went missing from the playground.
Hospitals across the city received a security alert about a suspicious package at the train station.
I get a daily news alert from the BBC app on my phone every morning.
- warning
broader; can be spoken, written, or implied
- notification
neutral message; not necessarily about danger
- alarm
often a sound or stronger emotional response
文法句型
a [type] alert
issue / receive an alert
用法筆記
The most common modern use is digital: app notifications, weather warnings, amber alerts. Often paired with verbs like 'issue', 'send', 'receive', 'get'. Distinct from sense 2: this is the warning message itself, not the state of being prepared.
常見錯誤
2. a condition in which a group such as soldiers, police, or staff is fully ready t
a condition in which a group such as soldiers, police, or staff is fully ready to act because something dangerous might happen.
Border troops were placed on high alert after the unexpected drone activity last night.
on high alert (idiomatic fixed phrase)
Hospitals across Tokyo went on full alert as the typhoon approached the coast.
on full alert
Airport staff remained on alert throughout the night following the bomb threat.
The mayor put fire crews on alert before the wildfires reached the edge of town.
- stand-down
the cancellation of an alert state
文法句型
on (high / full) alert
put / place on alert
用法筆記
Almost always appears in the prepositional phrase 'on (high/full) alert'. Subject is usually an organisation, force, or group of professionals — not a single private person. Distinct from sense 1: this describes the readiness, not the warning message itself.
常見錯誤
alert — verb
1. to tell someone quickly that a dangerous or urgent situation is happening, so th
to tell someone quickly that a dangerous or urgent situation is happening, so they can act before it gets worse.
A neighbour alerted the fire brigade after she smelled smoke coming from the empty house.
alert + emergency service
Lifeguards quickly alerted swimmers to the sudden change in the tide.
alert + sb + to + danger
The bank alerted Mr. Chen by text message when an unusual payment left his account.
Witnesses alerted the police as soon as they saw the white van speed past the school.
文法句型
alert + somebody
alert + somebody + to + noun
用法筆記
Always transitive — you alert SOMEONE, not just 'alert' on its own. The thing you warn about goes after 'to' (alert sb to a problem) or in a 'that' clause (alert sb that something has happened).
常見錯誤
2. to make someone notice or become aware of something important, often a problem o
to make someone notice or become aware of something important, often a problem or fact they had missed.
The audit alerted senior managers to several gaps in the company's safety procedures.
alert + sb + to + a problem
Dr. Patel was alerted to the unusual test result by a junior nurse on the ward.
passive: be alerted to + noun
A short article in the local paper first alerted residents to the planned road closure.
Her trembling hands alerted me to how nervous she really was about the speech.
- inform
neutral; just gives information, no urgency
- make aware
plain phrasing; common in everyday speech
- draw attention to
focuses on pointing something out, not on warning
文法句型
alert + somebody + to + noun
be alerted to + noun
用法筆記
Frequently passive ('was alerted to'). Differs from sense 1 by scope: sense 1 warns of an urgent danger; sense 2 simply makes someone aware of a fact, problem, or detail they had not noticed. The trigger here can be a report, sign, or piece of evidence rather than an emergency.