1、Many animals undergo migration during certain times of the year.
许多动物在一年的某个时期会进行迁徙。
2、The government implemented new policies to control illegal migration.
政府实施了新的政策来控制非法移民。
3、There is a general migration of population from rural areas to urban areas.
人口普遍从农村地区迁往城市地区。