关于正格和七成的说法,我完全copy from 百度:
https://baike.baidu.com/item/%E5%85%AD%E8%A8%80%E7%BB%9D%E5%8F%A5/10331550
https://baike.baidu.com/item/%E9%A2%98%E8%A5%BF%E5%A4%AA%E4%B8%80%E5%AE%AB%E5%A3%81%E4%BA%8C%E9%A6%96/1095224