本文目录：
The number of players in the NBA
最佳答案：
NBA球员数量会因多种因素处于动态变化中。
- 历史总球员数量：截至2022年2月，有4706名球员至少打过一场NBA比赛。
- 单赛季常规球员数量：NBA有30支球队，每支球队常规赛大名单最多可有15名球员，按此计算联盟常规球员有450名。但从实际参赛人数看，近年来因双向合同等因素，参赛球员数量超过此数。比如2022-23赛季有560名球员，2021-22赛季有550名，2020-21赛季有543名。
- 包含双向合同球员数量：从2017-18赛季引入双向合同后，每支球队可在15名正式球员外，再签2名双向合同球员，这样30支球队最多可有510名球员。
- 特殊时期球员数量：在特殊情况下，如伤病潮严重时，球队还可使用困难特例签下10天短合同球员，会使联盟球员数量进一步增加，像2021年12月，NBA在册球员达到553人。
足球的起源英文版
the UK precursor to American Football, which is still happily played over here in the UK. There are two variants of rugby, namely Rugby Union and Rugby League, with one of the chief differences between the two being the number of players per team - 15 in Union and 13 in League, but thats not desperately relevant.To deal with Rugby Union, a rugby team is divided into the forwards - 8 big hulking guys who form the "scrum" (hence the term line of scrimmage) - and the backs who line up diagonally across the pitch whenever a scrum takes place, but who must be behind the ball. The 7 backs are themselves sub-divided into 2 half-backs (the scrum-half, the guy who feeds the ball into the scrum and distributes it down the line of backs if his side should win the ball, and the fly-half, sometimes known as the standoff-half, whos next down the line), 4 three-quarter backs (the inside and outside centres and a left and right wing) and right at the rear, the full back.
So its all about the positioning of the players on a rugby pitch. I suspect that American Football adopted and amended these terms.
