Theirs is probably the longest migration flight. 这也许是最远的迁移飞行。
Migration of the seismic activity is found before a big event. 发现了大震前地震活动性的迁移。
I freely admit the former existence of many islands, now buried beneath the sea, which may have served as haltingplaces for plants and for many animals during their migration. 我直率地承认,从前曾存在过许多岛屿可作为植物和许多动物迁移中歇足之地,现在都已埋在海下了。