races of man

• 人种

races of man的用法和样例：

例句

1. It's often difficult to draw a clear dividing line between these five races.
   这五个人种经常很难区分。
2. Will they mix with each other into a single race or divide into more races?
   是融合成一个单一的人种还是会分化出更多的人种？