为属性分配多个值

I am using rowlex in my project. I have a property assigned to an individual in my RDF file, which has a value. For example for individual 'Student', there is a property 'isMemberOf', with value of a class uri 'class00021'. Then I want to add a second value to this property. For instance a 'Project' value with uri 'proj000052'.I am using rowlex in my project. I have a prope