Thousands of years ago, people used different ways to measure things. Some people used the sof their king s foot or hand to measure things. After the king died, they used the new king's foot or hand, and so on. However, it was ifor people to tell the exact size of a thing. In 1584, the Dutch(荷兰的) engineer Simon Steven started to think about a set of measures, The measures used the number ten. H, it was just an idea. No one was interested in his idea at that time.

    About two hundred years later, the French scientists created a nsystem of units, using Simon Steven's idea. Around this time, the French scientists wout the length of a metre and began to use metres to measure length. They decided to ca hundredth of a metre a centimetre and a thousand metres a kilometre.