Open your thumb and middle finger, and the distance between the two ends (about five inches long) is "one foot". Ru Zhijuan's "Three Walks to Zhuang Yan": "The father of Laiquan, with a small tobacco pouch all day long, worked hard."

ù tuǒ: the length of the two arms extending to the left and right. Commonly known as double-arm horizontal measuring rope, the number is one and two. See the addition of Wu Renchen's thesaurus in Qing Dynasty.

Step: the distance between your feet when walking. Biography of Mr. Adult by Ruan Wei in the Three Kingdoms: "Take Wan Li as a step and Chitose as a year." Zhuzi School Volume II: "It's like walking on a round ground. One person is too anxious, one person is less than one step, and the other person is very slow, and it is several steps away. " Jie Yuan's "The West Chamber" in eastern Shanxi Province, Volume 6: "The horse goes west and the car drags east. The couple are only one step away. "