A hundred years ago, the we now call football did not exist. American football started during a between two colleges. The teams had got together to play what they called "football", but each team played by different rules. One team played what we now call soccer (英式足球). The other played what we now call rugby (橄榄球).
Both s had been invented a thousand years before. In the first kind of football ever played, all the men from one village tried to kick a ball into another village. The men of the second village tried to kick the ball into the first. Hundreds of people joined in, running everywhere, ruining crops and knocking down fences. In time, people agreed on some rules to keep order, but many rules were left open to change. Different rules developed in different places.
When the two colleges met to play football, each followed its own rules. They mixed the s together and invented a new . A hundred years later we call that American football.
In what ways do you suppose the we know now will have changed in another hundred years
"Both s" at the beginning of the second paragraph refers to ______.