?劝某人警惕
... on one's guard 警惕 put someone on his guard 劝某人警惕,让某人提... lie on one's guard 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。