1 to test a shuttle , use a full underhand stroke which makes contact with the shuttle over the back boundary line 测试一个羽毛球,采用低手击球使得羽毛球超过后界。
Extension of the court by l 1 2 feet on both sides for doubles play . area between the back boundary line and the long service line for doubles 单打与双打界线间空地网球场边的平行狭长地带,加宽了界内场地,可进行双打比赛