alert/ə'lɜːt $ ə'lɜːrt/

a. always watching and ready to notice anything unusual, dangerous, etc.

v. warn sb about a danger or problem

a. 警觉的，警惕的：An alert security guard stopped the thief. 一名警觉的保安截住了盗贼。

v. 向…报警；使警觉，使警惕：They alerted the police when some strangers appeared in the village. 当一些陌生人出现在村子时，他们向警察报了警。

on (the) alert (for sth) 警戒着，防备着；密切注意着：We need to be on alert for another flood. 我们得防备下一次洪水。

音组-ert/-ɜːt $ -ɜːrt/

alert; desert (v.); dessert