如果是普通子类，增加一个实例的时候，（事先建好关联的)属性都会自动出来

如果增加一个thing的intance，那么必须手工添加属性，才会出现在实例里

这里有2个问题：
1。正常情况下，会有人建thing的实例吗？

2。属性的域是否可以有多个？（好像可以）

建立属性的时候，是否一定要把默认的定义域thing用其他的定义域替换掉（似乎是默认操作）？保留thing在定义域列表里会有什么问题吗？

之后我想把thing从定义域移除的时候，得到java异常，提示说owl可能不相容了，最好另存

An instance of Thing is kind of the universal instance, however I never created an instance of Thing before.

The initial domain of a property is certainly Thing, so there is no need to remove Thing from the domain unless you restrict the domain to a specific subclass of  Thing.

Another question: If I am going to use ontology to facilitate biology data mining, would it be better to create two ontologies (biology, and data mining) rather than one (universal framework of bioDataMining)?

To what extent Instantiating the ontology to instances will benefit my framework? Or can I implement it without much instances (to write my thesis)

I know this is a abstract question, still hope I can get some hints.

As for the instantiation, it is still up to you. If your thesis are working on TBox only, then few or even no instance will be acceptable. Otherwise you may need to instantiate the classes on demand.