As the planes sped by, we were impressed by the perfect symmetry of their V-formation.
当飞机飞过时,那完美匀称的V形排列给我们留下了深刻的印象。
2
Since 1914, scientists have known that birds flying in formation—a V-shape—expend less energy.
自1914年以来,科学家们已经知道,以V字形队形飞行的鸟类消耗的能量更少。
3
Since 1914, and a seminal paper by a German researcher called Carl Wieselsberger, scientists have known that birds flying in formation—a V-shape, echelon or otherwise—expend less energy.