?严密监视
... as sharp as a needle很有鉴别力的, 异常精明的 keep a sharp lookout严密监视 One’s eyes are sharp眼光锐利 ...
?戒备
戒备 guard; take precautions; be on the alert; keep a sharp lookout; exercise vigil ..
小心提防
英汉双解词典包含3185865条英汉词条,基本涵盖了全部常用单词的翻译及用法,是英语学习的有利工具。