backspin是什么意思
音标:英 [ˈbækspɪn]美 [ˈbækˌspɪn]
(球,轮等的)逆转, 倒旋
spin (usually of a moving ball) that retards or reverses the forward motion
backspin的用法和例句：
1.
You need to throw that five point seven feet in the air at a 60degree angle with backspin.
你需要向上六十度角 抛出1.7米 伴有回旋
