Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
civilizations –n. well-organized and developed societies that have existed through time
stumbled upon –v. to find something unexpectedly
navigational –adj. related to find one's way by sea, land or air
route –n. a way to get from one place to another
pirates –n. someone who attacks and steals from ships at sea
