这两种化合物的分子结构互为镜像，因此被称为对映异构体。

These two compounds are ___enantiomers because their molecular structures are mirror images of each other.

这两种药物分子互为镜像，形成一对对映异构体。

These two drug molecules are mirror images of each other, forming a pair of ___enantiomers.