Because we find the same movement in fish tails when they are moving, or in birds' wings.

因为鱼尾和鸟翼也有着相同的运动方式。

And the researchers found that as fish heads appear to decrease in the early 1200s, fish tails dramatically increased—a sign of importation.

研究人员们还发现随着1200年代出土数量鱼头的减少，而鱼尾却显著增加—这是一个鱼类进口贸易的标志。

Turning " a near-infrared light laser" on and off causes the fish's tail to move back and forth, the American Chemical Society said.

美国化学会表示，打开和关闭 “近红外线激光” 会使鱼的尾巴来回移动。

He can seem remote, the frock coat, the velvet collar, the fish tail beard, the bow tie.

礼服大衣、天鹅绒领、鱼尾胡须、领结，他看起来很遥远。

They leered at Harry as he swam past; one or two of them emerged from their caves to watch him better, their powerful, silver fish tails beating the water, spears clutched in their hands.

哈利游过时，他们朝他不怀好意地笑着。有一两个为了看得更清楚些，还从洞穴里跑出来，手里拿着长矛，用粗壮有力的银色鱼尾拍击着湖水。