A leading Nigerian blood specialist is the WHO . cancer. is alarmed at the growing numbers of cases of cancer - the name given to a class of diseases characterized by the uncontrolled growth of cells, which then form tumors.

VOA: standard.2010.06.16

Notice the form of it, it's just the name of the class followed by open paren, close paren, treating it like a function.

我该怎么来使用类呢？,好，我可以像调用方法,一样调用类，你可以在下面看到，创建一个名为。

麻省理工公开课 - 计算机科学及编程导论课程节选

The kinds of proteins that sit on a cell surface and form adhesion junctions with neighboring cells, that's one class of cells on the surface.

这些蛋白位于细胞表面,和相邻的细胞建立粘附链接,这是细胞的一个种类

耶鲁公开课 - 生物医学工程探索课程节选