Virtual library is mentioned comparatively with real library, and is a basic characteristic of modern library, while real library is a basic support of modern library.

• 虚拟图书馆是实体图书馆的相对物,是现代图书馆的基本特征。 实体图书馆是虚拟图书馆的相对物,是现代图书馆的基本依托。