peribole

例句：

1. 1. The bacterium has a flagellum thathelps it move through the water.
   这种细菌有一个鞭毛，帮助它在水中移动。
2. 2. Theflagellum of the sperm is responsiblefor propelling the egg towards theovum.
   精子的鞭毛负责将卵子推向卵细胞。
3. 3. The flagellum is visible asa thin, whip-likestructure at the end of the cell.
   鞭毛作为细胞末端的一根细长的鞭子状结构可见。