橄榄球球场长91米。开场时，一方将球由自己的半场开至对方的半场。这时，开球方的跑锋接到球后开始朝对方阵区狂奔，直到对方防守球员将他扑倒，这个时候停表。之后攻方有4次机会将球往前移动9米。如果攻方未能用这4次机会前进9米就交换持球权。当一方努力带球朝对方半场前进时他们就是攻方。而阻止攻方带球前进的就是守方。比赛时，攻守方各派出11名球员。但是，一支完整的橄榄球队总共有46名球员，比赛时可以轮换出场，每名球员都有自己专门的位置和技术。

    American football has been America's favorite sport since 1972, when it overtook baseball. Most games are played on Sunday afternoons, at which time family and friends gather together to watch.Most large cities have a professional football team, and people usually support the team from their hometown. College and even high school football are also extremely popular; some of the better college football teams draw a crowd of around 100,000 fans each game, while millions more watch on television. However the most popular league is the professional football league, known as the National Football League (NFL). There are 32 teams that compete in a four month long season every year which culminates with the Super Bowl, a game played between the two best teams each year. The Super Bowl is one of the biggest social events of the year in America, people all over the country hold Super Bowl parties to watch the game together. ......