coarse migration

例句：

1. 1.The coarse migration of the river has caused a lot of problems for the local people.
   河流的粗粒迁移给当地人民带来了很多问题。
2. 2.Coarse migration is an important factor influencing the distribution of species.
   粗粒迁移是影响物种分布的一个重要因素。
3. 3.The coarse migration of the river has caused a lot of problems for the local people.
   河流的粗粒迁移给当地人民带来了很多问题。