lǎo shì / chèng / shàng / yǒu / yī ge / zhǔn xīng / yòng lái / pàn duàn / zhòng liàng / shì fǒu / zhǔn què

老式秤上有一个准星，用来判断重量是否准确。

There is a zero point mark on the old-style steelyard, used to judge whether the weight is accurate.