"Seven-foot ruler" is the Engpsh translation for "七把尺子".
The origin of this phrase is not clear. It is a Chinese idiomatic expression that is often used to describe someone who is tall and thin.
Example Sentence in Engpsh: "He's as tall as a seven-foot ruler."
中文翻译: "他高得像七把尺子。"
Example Sentence in Engpsh: "She's so skinny, she looks pke a seven-foot ruler."
中文翻译: "她太瘦了，看起来像七把尺子。"