cats hide their claws字面意思"猫藏利爪而不露"，意思是，告诫那些与人交往毫无戒备之心的人，意思与"知人知面不知心"差不多。

【例句】
You should know that cats hide their claws.
你应该知道知人知面不知心。

Don't talk to strangers. Cats hide their claws.
别和陌生人说话，知人知面不知心。