羽毛球的球 英文：
Badminton is a racquet sport played using racquets to hit a shuttlecock across a net. It is played by either two opposing players (singles) or two opposing pairs (doubles), who take positions on opposite halves of a rectangular court divided by a net. Players score points by striking the shuttlecock with their racquet so that it passes over the net and lands in their opponents' half of the court. A rally ends once the shuttlecock has struck the floor. The shuttlecock is a feathered or plastic projectile which flies differently from the balls used in most other sports.
In badminton, players use lightweight racquets made of carbon-fibre composite or aluminum to hit a shuttlecock. The shuttlecock is a small, round, lightweight projectile with an open conical shape, usually made from goose feathers. It weighs between 4.74 and 5.50 grams and its circumference is between 77 and 80 millimeters. The cork base is covered with 16 to 20 feathers that are usually held together with a rubber band. It is designed to fly differently from the balls used in other sports and does not bounce. Instead, it drifts in the air and falls slowly to the ground. To play badminton, players must be able to hit the shuttlecock accurately and consistently and have good footwork to move quickly around the court.
双打羽毛球规则边界线：
双打羽毛球规则边界线是指双打羽毛球比赛中，球场的边界线。球场可以是室内或室外，边界线可以是实心线或虚线。
实心线：实心线位于比赛场地的最外边，用来指示球场的边界，在比赛中，球如果碰到实心线，则为出界，则得分者不得分。
虚线：虚线位于球场的中央，它们用来划分球场的左右两侧，在比赛中，球如果碰到虚线，则为技术性出界，则得分者仍可得分。
另外，球场的宽度规定为6.1米，深度规定为13.4米，球门的宽度为2米，深度为6米。