The antonyms have distinct nuances: *Awake* refers to being conscious, *alert* refers to being watchful, and *sensitive* refers to being easily affected. Use these words in medical contexts to describe a patient's state of consciousness, in safety and security contexts to describe a person's level of vigilance, and in environmental contexts to describe a person's reaction to external factors.

그녀는 시험을 위해 밤새도록 *깨어* 있었습니다.

彼女は一晩中試験のために勉強していました。

She was *awake* all night studying for her exam.

경비원은 *경계*했고 의심스러운 활동을 즉시 알아차렸습니다.

警備員は*警戒*し、疑わしい活動にすぐに気づきました。

The security guard was *alert* and noticed the suspicious activity immediately.

그녀의 피부는 태양에 *민감*했기 때문에 항상 자외선 차단제를 바르고 다녔습니다.

彼女の肌は太陽に*敏感*だったので、彼女はいつも日焼け止めを塗っていました。

Her skin was *sensitive* to the sun, so she always wore sunscreen.