At first balls were made of grass or leaves held together by vines.

起初，球是用藤条把草或树叶捆在一起做成的。

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The Eskimos played soccer on ice and used balls filled with caribou hair and grass.

爱斯基摩人在冰上踢球，他们用的是驯鹿的毛发和草填充成的球。

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At first balls were made of grass or leaves held together by vines. Later they were made of pieces of animal skin sewed together and stuffed with feathers or hay.

起初，球是用藤条把草或树叶捆在一起做成的。后来，人们将动物的皮缝合起来，里面塞进羽毛或干草做成球。

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Some soccer teams wet the field before a match to make the ball roll faster, while baseball teams grow out grass to slow ground balls.

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White balls discoloured by the grass are difficult for fielders and batsmen to see in certain light conditions.

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"He used to (serve and volley), but I think the conditions of the grass have changed so much -- the balls are probably heavier, the courts are much, much slower, so there is far less serve and volley, " Henman told CNN.

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