You just need to survey the right subgroups of voters.

您只需要调查正确选民子群。

Categories. Types or subgroups. An everyday encounter with categories is types of food, fruits, vegetables, carbohydrates, proteins, and so on. These are food categories.

别。或子群。日常遇到是食，、蔬菜、碳化合、蛋白质，等等。这些都是食别。

They took over niches that had been left vacant by the Great Dying, and radiated across Pangea, onto every modern continent, into a host of subgroups.

他们接管了因大消亡而空置生态位，并辐射到盘古大陆， 进入每一个现代大陆，形成许多子群。