Ключевые слова: 20, 30, american, american football, arena, artificial, astroturf, athletics, color, copy space, day, empty, field, firstdown, football, football field, football stadium, full, grass, green, hash marks, horizontal, line, markings, nobody, numbers, outdoors, outside, sideline, sport, sports, stadium, thirty, touchdown, turf, twenty, yard, yard line, yardline, yardlines,