Question

alert
a.lert  AHD[…-lûrt“]   DJ[*6lT8t]  KK[*6lPt]
adj.（形容词）
1.Vigilantly attentive; watchful:
    警觉的，警惕的；注意的：
    alert to danger; an alert bank guard.See Synonyms at &b{aware}
    警惕危险；警觉的银行保安人员参见aware
2.Mentally responsive and perceptive; quick.
    思维敏捷的：思维反应迅速且感觉灵敏的；快速敏捷的
3.Brisk or lively in action:
    活泼的：行动轻快或有活力的：
    the bird's alert hopping from branch to branch.
    小鸟在树枝间欢快地跳跃
n.（名词）
1.A signal that warns of attack or danger:
    警报：警告进攻或危险的信号：
    Sirens sounded the alert for an air raid.See Synonyms at &b{alarm}
    空袭警报的警笛响起参见alarm
2.A condition or period of heightened watchfulness or preparation for action:
    警戒状态：高度警惕或准备随时行动的状态或阶段：
    Nuclear-armed bombers were put on alert during the crisis.
    核武装轰炸机在危机期间负责警戒
v.tr.（及物动词）  a.lert.ed,a.lert.ing,a.lerts
    To notify of approaching danger or action; warn:
    向…报警：对临近的危险或行动发出通知；警告：
    a flashing red light that alerted motorists to trouble ahead.
    闪烁的红灯警告摩托车手前面有危险
IDIOMS
▪on the alert: Watchful and prepared for danger, emergency, or opportunity:
    警戒着，防备着：注意着且防备着危险、意外或机会：
    bird watchers on the alert for a rare species.
    看守者人密切注意稀有鸟类
ORIGIN
1.Frenchalerte
    法语alerte
2.from Italianall' erta [on the lookout]
    源自 意大利语all' erta [密切注意]
3.alla [to the, on the]  from Latinad illam [to that]  ad- [ad-]  illam [accusative of] illa [that] * see  al-¹
    alla [对…，在…之上]  源自 拉丁语ad illam [对那个]  ad- [前缀，表“朝向”]  illam  [] illa的宾格 [那] *参见 al-¹
4.erta [lookout] [from past participle of] ergere [to raise]  from Latin¶rigere * see  erect
    erta [注意]  [] 源自ergere的过去分词 [举起]  源自 拉丁语¶rigere *参见erect