Bowling

Bowling, indoor sport, played by rolling a ball down an alley（球道） at ten pins. Bowling is one of the most popular sports in the United States, where there are thousands of recreational(娱乐) leagues.

A regulation bowling alley is made of polished wood and measures 41 to 42 in. (104.1 to 106.7 cm) wide and 60 ft (18.3 m) from the foul line（边界线）. The ball is delivered in the alley and to the center of the head pin (保龄球的中央瓶). It is made of rubber composite or plastic, which has three or four finger holes.

A game consists of 10 frames （局）, with two balls allowed a bowler in each frame. Each pin knocked down counts one point. Toppling all pins（所有瓶都倒了） with the first ball is a strike（全中） and scores 10 points plus the total of the next two balls. Clearing the alley with two balls is a spare（两次全中） and scores 10 points plus the next roll. A perfect game, 300 points, requires 12 consecutive（连续的） strikes.

Forerunners of modern bowling date to at least 5200 in Egypt. A form similar to today's, though using nine pins, was popular in Germany in the Middle Ages. Dutch settlers probably introduced the game in America. The invention of automatic pin-setting machines and, later in the 20th cent., television, spurred（带动了） the growth of bowling.