yǐ shèn wéi jiàn
to take caution as the key (idiom); to proceed very carefully
以
yǐ
abbr. for Israel 以色列[Yi3 se4 lie4]
慎
shèn
old variant of 慎[shen4]
为
wéi
variant of 為|为[wei2]
键
jiàn
key (on a piano or computer keyboard)
