In the year of 1870, a sort of ball made of feather and wood as well as a bat woven with strings were invented.
1870年，出现了用羽毛、软木做的球和穿弦的球拍。
When a tennis ball stays on your strings for 4/1000 of a second it is impossible to do this.
当网球在你的拍线上停留4/1000秒的情况下这是不可能做到的。
When a tennis ball stays on your strings for 4/1000 of a second it is impossible to do this.
当网球在你的拍线上停留4/1000秒的情况下这是不可能做到的。
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