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Balls should be good for at least six sets, and for more for the average player. But if the rallies are long, they do not last as long as this. There is a fuzz on the surface that wears off on the hard court.
球应该是好至少六套，并为更多的平均球员。但如果反弹时间很长，就不会持续这么久。在硬地上有一层细毛逐渐消失了。