Under domestication monstrosities sometimes occur which resemble normal structures in widely different animals.

在驯化过程中， 有时会出现类似于不同动物正常结构的畸形。

Studies of the normal structure and functions of the body are the basis for all medical sciences.

只有了解了正常情况是什么样子，我们才能在疾病发生的时候分析出是哪里出的问题。

The frequent presence of fourteen or even sixteen tail-feathers in the pouter may be considered as a variation representing the normal structure of another race, the fantail.

pouter 中经常出现十四甚至十六根尾羽可以被认为是代表另一个种族的正常结构的变异， fantail。