n.警觉，清醒，机警

He was wide awake and alert after a good night's sleep.
他经过一夜好眠后精神饱满，十分清醒。
The teacher entered the classroom, and instantly the students became alert.
老师走进教室，学生们立刻变得警觉起来。
She took a sip of coffee to maintain her alertness during the long meeting.
她喝了口咖啡以保持在冗长会议中的清醒。
The driver needed to stay alert on the icy roads for safety.
司机在结冰的路上必须保持高度警觉以确保安全。
Students were asked to maintain alertness during the chemistry lab to avoid accidents.
学生们被要求在化学实验室保持警觉，以防发生意外。
The soldier was trained to be highly alert at all times, ready to react instantly.
那名士兵受过训练，始终保持高度警觉，随时准备反应。
The medication helped him regain his alertness after a bout of drowsiness.
这种药物帮助他在昏昏欲睡后恢复了清醒。
An alert observer can spot potential problems before they become major issues.
敏锐的观察者能在问题恶化前发现它们。
The children were encouraged to maintain alertness during outdoor activities to prevent injuries.
孩子们被鼓励在户外活动中保持警觉，以防止受伤。
Her alertness was a key factor in her successful navigation through the jungle.
她的警觉性是她在丛林中成功导航的关键因素。