长期以来,各国都有不同的长度单位,如中国的市制单位寸、尺、丈,英国、美国等国家常用的英寸、英尺、英里等.由于各国单位不一致,给国际交流带来很多不便.1960年的国际计量大会通过了一套单位制,称为国际单位制,长度的国际单位很快在世界上很多国家普及起来. For a long time, all countries have different length units, such as the Chinese municipal units, feet, feet, Britain, the United States and other countries commonly used in inches, feet, miles, etc.. Due to inconsistent units in various countries, bringing a lot of inconvenience to international exchanges. The 1960’s International Metrology Congress adopted a system of units known as the International System of Units. International units of length soon became popular in many countries around the world.